WorldWideScience

Sample records for on-line laser spectroscopy

  1. On-line laser spectroscopy with thermal atomic beams

    CERN Document Server

    Thibault, C; De Saint-Simon, M; Duong, H T; Guimbal, P; Huber, G; Jacquinot, P; Juncar, P; Klapisch, Robert; Liberman, S; Pesnelle, A; Pillet, P; Pinard, J; Serre, J M; Touchard, F; Vialle, J L

    1981-01-01

    On-line high resolution laser spectroscopy experiments have been performed in which the light from a CW tunable dye laser interacts at right angles with a thermal atomic beam. /sup 76-98/Rb, /sup 118-145 /Cs and /sup 208-213/Fr have been studied using the ionic beam delivered by the ISOLDE on-line mass separator at CERN while /sup 30-31/Na and /sup 38-47/K have been studied by setting the apparatus directly on-line with the PS 20 GeV proton beam. The principle of the method is briefly explained and some results concerning nuclear structure are given. The hyperfine structure, spins and isotope shifts of the alkali isotopes and isomers are measured. (8 refs).

  2. On-line Excited-State Laser Spectroscopy of Trapped Short-Lived Ra$^+$ Ions

    CERN Document Server

    Versolato, O O; Wansbeek, L W; Berg, J E van den; van der Hoek, D J; Jungmann, K; Kruithof, W L; Onderwater, C J G; Sahoo, B K; Santra, B; Shidling, P D; Timmermans, R G E; Willmann, L; Wilschut, H W

    2010-01-01

    As an important step towards an atomic parity violation experiment in one single trapped Ra$^+$ ion, laser spectroscopy experiments were performed with on-line produced short-lived $^{212,213,214}$Ra$^+$ ions. The isotope shift of the $6\\,^2$D$_{3/2}$\\,-\\,$7\\,^2$P$_{1/2}$ and $6\\,^2$D$_{3/2}$\\,-\\,$7\\,^2$P$_{3/2}$ transitions and the hyperfine structure constant of the $7\\,^2$S$_{1/2}$ and $6\\,^2$D$_{3/2}$ states in $^{213}$Ra$^+$ were measured. These values provide a benchmark for the required atomic theory. A lower limit of $232(4)$ ms for the lifetime of the metastable $6\\,^2$D$_{5/2}$ state was measured by optical shelving.

  3. Laser-induced breakdown spectroscopy for on-line control of selective removal of cobalt binder from tungsten carbide hardmetal by pulsed UV laser surface ablation

    Science.gov (United States)

    Li, Tiejun; Lou, Qihong; Wei, Yunrong; Huang, Feng; Dong, Jingxing; Liu, Jingru

    2001-09-01

    Laser-induced breakdown spectroscopy (LIBS) was successfully used in on-line control of selective removal of cobalt from tungsten carbide hardmetal by pulsed UV laser surface ablation. The dependence of LIBS on number of laser shots was investigated at different laser fluences. The optimal laser fluence of 2.5 J/cm 2 suited for selective removal of cobalt from surface layer of hardmetal was confirmed. The result sample was also subject to different post-examinations to evaluate the feasibility of the application of LIBS in this laser ablation process. It was demonstrated that, monitoring of the emission intensity of cobalt lines could be used as a control parameter for selective removal of cobalt from surface layer of hardmetal by pulsed UV laser. The on-line implementation of the spectroscopic technique LIBS to the surface-ablation process provided important information about the optimal-ablation parameters.

  4. New on-line method for water isotope analysis of speleothem fluid inclusions using laser absorption spectroscopy (WS-CRDS)

    Science.gov (United States)

    Affolter, S.; Fleitmann, D.; Leuenberger, M.

    2014-01-01

    A new online method to analyse water isotopes of speleothem fluid inclusions using a wavelength scanned cavity ring down spectroscopy (WS-CRDS) instrument is presented. This novel technique allows us to simultaneously measure hydrogen and oxygen isotopes for a released aliquot of water. To do so, we designed a new simple line that allows the on-line water extraction and isotope analysis of speleothem samples. The specificity of the method lies in the fact that fluid inclusions release is made on a standard water background, which mainly improves the δD reliability. To saturate the line, a peristaltic pump continuously injects standard water into the line that is permanently heated to 140 °C and flushed with dry nitrogen gas. This permits instantaneous and complete vaporisation of the standard water resulting in an artificial water background with well-known δD and δ18O values. The speleothem sample is placed into a copper tube, attached to the line and after system stabilisation is crushed using a simple hydraulic device to liberate speleothem fluid inclusions water. The released water is carried by the nitrogen/standard water gas stream directly to a Picarro L1102-i for isotope determination. To test the accuracy and reproducibility of the line and to measure standard water during speleothem measurements a syringe injection unit was added to the line. Peak evaluation is done similarly as in gas chromatography to obtain δD and δ18O isotopic composition of measured water aliquots. Precision is better than 1.5‰ for δD and 0.4‰ for δ18O for water measurement for an extended range (-210 to 0‰ for δD and -27 to 0‰ for δ18O) primarily dependent on the amount of water released from speleothem fluid inclusions and secondarily on the isotopic composition of the sample. The results show that WS-CRDS technology is suitable for speleothem fluid inclusion measurements and gives results that are comparable to Isotope Ratio Mass Spectrometry (IRMS) technique.

  5. Laser spectroscopy

    CERN Document Server

    Demtröder, Wolfgang

    Keeping abreast of the latest techniques and applications, this new edition of the standard reference and graduate text on laser spectroscopy has been completely revised and expanded. While the general concept is unchanged, the new edition features a broad array of new material, e.g., ultrafast lasers (atto- and femto-second lasers) and parametric oscillators, coherent matter waves, Doppler-free Fourier spectroscopy with optical frequency combs, interference spectroscopy, quantum optics, the interferometric detection of gravitational waves and still more applications in chemical analysis, medical diagnostics, and engineering.

  6. Laser spectroscopy

    CERN Document Server

    Demtröder, Wolfgang

    2008-01-01

    Keeping abreast of the latest techniques and applications, this new edition of the standard reference and graduate text on laser spectroscopy has been completely revised and expanded. While the general concept is unchanged, the new edition features a broad array of new material, e.g., frequency doubling in external cavities, reliable cw-parametric oscillators, tunable narrow-band UV sources, more sensitive detection techniques, tunable femtosecond and sub-femtosecond lasers (X-ray region and the attosecond range), control of atomic and molecular excitations, frequency combs able to synchronize independent femtosecond lasers, coherent matter waves, and still more applications in chemical analysis, medical diagnostics, and engineering.

  7. The Leuven isotope separator on-line laser ion source

    CERN Document Server

    Kudryavtsev, Y; Franchoo, S; Huyse, M; Gentens, J; Kruglov, K; Müller, W F; Prasad, N V S; Raabe, R; Reusen, I; Van den Bergh, P; Van Duppen, P; Van Roosbroeck, J; Vermeeren, L; Weissman, L

    2002-01-01

    An element-selective laser ion source has been used to produce beams of exotic radioactive nuclei and to study their decay properties. The operational principle of the ion source is based on selective resonant laser ionization of nuclear reaction products thermalized and neutralized in a noble gas at high pressure. The ion source has been installed at the Leuven Isotope Separator On-Line (LISOL), which is coupled on-line to the cyclotron accelerator at Louvain-la-Neuve. sup 5 sup 4 sup , sup 5 sup 5 Ni and sup 5 sup 4 sup , sup 5 sup 5 Co isotopes were produced in light-ion-induced fusion reactions. Exotic nickel, cobalt and copper nuclei were produced in proton-induced fission of sup 2 sup 3 sup 8 U. The b decay of the sup 6 sup 8 sup - sup 7 sup 4 Ni, sup 6 sup 7 sup - sup 7 sup 0 Co, sup 7 sup 0 sup - sup 7 sup 5 Cu and sup 1 sup 1 sup 0 sup - sup 1 sup 1 sup 4 Rh isotopes has been studied by means of beta-gamma and gamma-gamma spectroscopy. Recently, the laser ion source has been used to produce neutron-d...

  8. Tunable diode laser absorption spectroscopy-based tomography system for on-line monitoring of two-dimensional distributions of temperature and H{sub 2}O mole fraction

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Lijun, E-mail: lijunxu@buaa.edu.cn; Liu, Chang; Jing, Wenyang; Cao, Zhang [School of Instrument Science and Opto-Electronic Engineering, Beihang University, Beijing 100191 (China); Ministry of Education’s Key Laboratory of Precision Opto-Mechatronics Technology, Beijing 100191 (China); Xue, Xin; Lin, Yuzhen [School of Energy and Power Engineering, Beihang University, Beijing 100191 (China)

    2016-01-15

    To monitor two-dimensional (2D) distributions of temperature and H{sub 2}O mole fraction, an on-line tomography system based on tunable diode laser absorption spectroscopy (TDLAS) was developed. To the best of the authors’ knowledge, this is the first report on a multi-view TDLAS-based system for simultaneous tomographic visualization of temperature and H{sub 2}O mole fraction in real time. The system consists of two distributed feedback (DFB) laser diodes, a tomographic sensor, electronic circuits, and a computer. The central frequencies of the two DFB laser diodes are at 7444.36 cm{sup −1} (1343.3 nm) and 7185.6 cm{sup −1} (1391.67 nm), respectively. The tomographic sensor is used to generate fan-beam illumination from five views and to produce 60 ray measurements. The electronic circuits not only provide stable temperature and precise current controlling signals for the laser diodes but also can accurately sample the transmitted laser intensities and extract integrated absorbances in real time. Finally, the integrated absorbances are transferred to the computer, in which the 2D distributions of temperature and H{sub 2}O mole fraction are reconstructed by using a modified Landweber algorithm. In the experiments, the TDLAS-based tomography system was validated by using asymmetric premixed flames with fixed and time-varying equivalent ratios, respectively. The results demonstrate that the system is able to reconstruct the profiles of the 2D distributions of temperature and H{sub 2}O mole fraction of the flame and effectively capture the dynamics of the combustion process, which exhibits good potential for flame monitoring and on-line combustion diagnosis.

  9. [Techniques of on-line monitoring volatile organic compounds in ambient air with optical spectroscopy].

    Science.gov (United States)

    Du, Zhen-Hui; Zhai, Ya-Qiong; Li, Jin-Yi; Hu, Bo

    2009-12-01

    Volatile organic compounds (VOCs) are harmful gaseous pollutants in the ambient air. The techniques of on-line monitoring VOCs are very significant for environment protection. Until now, there is no single technology that can meet all the needs of monitoring various VOCs. The characteristics and present situation of several optical methods, which can be applied to on-line monitoring VOCs, including non dispersive infrared (NDIR), Fourier transform infrared (FTIR) spectroscopy, differential optical absorption spectroscopy (DOAS), and laser spectroscopy were reviewed. Comparison was completed between the national standard methods and spectroscopic method for measuring VOCs. The main analysis was focused on the status and trends of tuning diode laser absorption spectroscopy (TDLAS) technology.

  10. In situ and on-line monitoring of CO in an industrial glass furnace by mid-infrared difference-frequency generation laser spectroscopy.

    Science.gov (United States)

    Khorsandi, Alireza; Willer, Ulrike; Wondraczek, Lothar; Schade, Wolfgang

    2004-12-10

    A compact mid-infrared (MIR) laser spectrometer based on difference-frequency generation (DFG) is applied as a portable and sensitive gas sensor for industrial process control and pollutant monitoring. We demonstrate the performance of such a MIR DFG gas sensor by recording the absorption spectra of the carbon monoxide (CO) P(28) absorption line in the atmosphere of a gas-fired glass melting furnace. For a gas temperature of approximately 1100 degrees C, the CO concentration in the recuperator channel is measured to be 400 parts per million.

  11. Development of on-line laser power monitoring system

    Science.gov (United States)

    Ding, Chien-Fang; Lee, Meng-Shiou; Li, Kuan-Ming

    2016-03-01

    Since the laser was invented, laser has been applied in many fields such as material processing, communication, measurement, biomedical engineering, defense industries and etc. Laser power is an important parameter in laser material processing, i.e. laser cutting, and laser drilling. However, the laser power is easily affected by the environment temperature, we tend to monitor the laser power status, ensuring there is an effective material processing. Besides, the response time of current laser power meters is too long, they cannot measure laser power accurately in a short time. To be more precisely, we can know the status of laser power and help us to achieve an effective material processing at the same time. To monitor the laser power, this study utilize a CMOS (Complementary metal-oxide-semiconductor) camera to develop an on-line laser power monitoring system. The CMOS camera captures images of incident laser beam after it is split and attenuated by beam splitter and neutral density filter. By comparing the average brightness of the beam spots and measurement results from laser power meter, laser power can be estimated. Under continuous measuring mode, the average measuring error is about 3%, and the response time is at least 3.6 second shorter than thermopile power meters; under trigger measuring mode which enables the CMOS camera to synchronize with intermittent laser output, the average measuring error is less than 3%, and the shortest response time is 20 millisecond.

  12. New on-line method for water isotope analysis of fluid inclusions in speleothems using laser absorption spectroscopy: Application to stalagmites from Borneo and Switzerland

    Science.gov (United States)

    Affolter, Stéphane; Fleitmann, Dominik; Nele Meckler, Anna; Leuenberger, Markus

    2014-05-01

    Speleothems are recognised as key continental archives for paleoclimate reconstructions. They contain fluid inclusions representing past drip water trapped in the calcite structure. Speleothem can be precisely dated and therefore the oxygen (δ18O) and hydrogen (δD) isotopes of fluid inclusions constitute powerful proxies for paleotemperature or to investigate changes in the moisture source over several interglacial-glacial cycles. To liberate fluid inclusion water and to analyse its isotopic composition, a new online extraction method developed at Bern is used. The principle can be summarised as follows: Prior to crushing, the sample is placed into a copper tube, fixed to the line previously heated to 140° C and flushed with a nitrogen and standard water mixture. Thereafter, the speleothem sample is crushed using a simple hydraulic crushing device and the released water from fluid inclusions is transferred by the nitrogen-standard water mixture flow to a Picarro L1102-i isotopic liquid water and water vapor analyser. The measuring principle is based on wavelength-scanned cavity ring-down spectroscopy (WS-CRDS) technology that allows us to simultaneously monitor hydrogen and oxygen isotopes. Reproducibility of standard water measurements is typically better than 1.5 o for δD and 0.4 o for δ18O. With this method, we successfully analysed δD and δ18O isotopic composition of a stalagmite from Northern Borneo (tropical West Pacific) covering almost two glacial-interglacial cycles from MIS 12 to early MIS 9 (460-330 ka) as well as recent samples from Switzerland and Borneo. These results are used in combination with calcite δ18O to reconstruct paleotemperature. Currently, we are measuring a stalagmite from Milandre cave (Jura, Switzerland) covering the Bølling-Allerød, Younger Dryas cold phase and the Holocene.

  13. Foundations of laser spectroscopy

    CERN Document Server

    Stenholm, Stig

    2005-01-01

    A simple presentation of the theoretical foundations of steady-state laser spectroscopy, this text helps students to apply theory to calculations with a systematic series of examples and exercises. 1984 edition.

  14. Laser spectroscopy of protonium

    CERN Document Server

    Hayano, R S

    1999-01-01

    High-precision laser spectroscopy of protonium (pp) is one of the future experiments being considered by ASACUSA collaboration at CERN AD. A possible scheme to produce protonium in vacuum and to detect laser transitions is presented, and implications of reaching high precision are discussed. (7 refs).

  15. Femtosecond laser spectroscopy

    CERN Document Server

    Hannaford, Peter

    2005-01-01

    As concepts and methodologies have evolved over the past two decades, the realm of ultrafast science has become vast and exciting and has impacted many areas of chemistry, biology and physics, and other fields such as materials science, electrical engineering, and optical communication. The field has recently exploded with the announcement of a series of remarkable new developments and advances. This volume surveys this recent growth in eleven chapters written by leading international researchers in the field. It includes sections on femtosecond optical frequency combs, soft x-ray femtosecond laser sources, and attosecond laser sources. In addition, the contributors address real-time spectroscopy of molecular vibrations with sub-5-fs pulses and multidimensional femtosecond coherent spectroscopies for studying molecular and electron dynamics. Novel methods for measuring and characterizing ultrashort laser pulses and ultrashort pulses of light are also described. The topics covered are revolutionizing the field...

  16. [The development of acetylene on-line monitoring technology based on laser absorption spectrum].

    Science.gov (United States)

    He, Ying; Zhang, Yu-jun; Kan, Rui-feng; Xia, Hui; Wang, Min; Cui, Xiao-juan; Chen, Jiu-ying; Chen, Dong; Liu, Wen-qing; Liu, Jian-guo

    2008-10-01

    As one of the materials in organic chemical industry, acetylene has been used in many aspects of chemical industry. But acetylene is a very dangerous inflammable and explosive gas, so it needs in-situ monitoring during industrial storage and production. Tunable diode laser absorption spectroscopy (TDLAS) technology has been widely used in atmospheric trace gases detection, because it has a lot of advantageous characteristics, such as high sensitivity, good selectivity, and rapid time response. The distribution characteristics of absorption lines of acetylene in near infrared band were studied, and then the system designing scheme of acetylene on-line monitoring based on near infrared tunable diode laser absorption spectroscopy technology was discussed in detail. Moreover, the system of experiment measurement was set up and the method of signal detection and the algorithm of concentration inversion were studied. In addition, the sample cell with a path length of 10 cm, and the acetylene of different known concentrations were measured. As a result, the detection limit obtained reached 1.46 cm3 x m(-3). Finally the dynamic detection experiment was carried out, and the measurement result is stable and reliable, so the design of the system is practicable through experiment analysis. On-line acetylene leakage monitoring system was developed based on the experiment, and it is suitable for giving a leakage alarm of acetylene during its storage, transportation and use.

  17. Laser spectroscopy of radium

    Energy Technology Data Exchange (ETDEWEB)

    Santra, Bodhaditya; Dammalapati, Umakanth; Jungmann, Klaus; Willmann, Lorenz [KVI, University of Groningen (Netherlands)

    2011-07-01

    Searches for permanent electric dipole moments (EDMs) of fundamental particles are sensitive probes of physics beyond the Standard Model. Fundamental EDMs can experience enhancements in atomic and molecular systems. In particular, isotopes of the heavy alkaline earth element radium exhibit the largest known enhancement factors for any atomic systems due to their atomic and nuclear structure. A sensitive search for EDMs will require an efficient use of the rare isotopes, which are available from radioactive sources or at rare isotope facilities like TRI{mu}P at KVI. Here, laser cooling and trapping methods play a crucial role. The main transitions from the ground state have been identified by laser spectroscopy. Nevertheless, the strongest cooling transitions 7s{sup 2} {sup 1}S{sub 0}-7s7p {sup 1}P{sub 1} suffers from strong leakage to metastable states, similar to the case of barium. We describe the experimental approach to determine the wavelength of the three needed repump transitions, which then will permit an efficient capture of radium atoms into a magneto optical trap.

  18. Laser Spectroscopy and Frequency Combs

    Science.gov (United States)

    Hänsch, Theodor W.; Picqué, Nathalie

    2013-12-01

    The spectrum of a frequency comb, commonly generated by a mode-locked femtosecond laser consists of several hundred thousand precisely evenly spaced spectral lines. Such laser frequency combs have revolutionized the art measuring the frequency of light, and they provide the long-missing clockwork for optical atomic clocks. The invention of the frequency comb technique has been motivated by precision laser spectroscopy of the simple hydrogen atom. The availability of commercial instruments is facilitating the evolution of new applications far beyond the original purpose. Laser combs are becoming powerful instruments for broadband molecular spectroscopy by dramatically improving the resolution and recording speed of Fourier spectrometers and by creating new opportunities for highly multiplexed nonlinear spectroscopy, such as two-photon spectroscopy or coherent Raman spectroscopy. Other emerging applications of frequency combs range from fundamental research in astronomy, chemistry, or attosecond science to telecommunications and satellite navigation.

  19. Two-step laser ionization schemes for in-gas laser ionization and spectroscopy of radioactive isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Kudryavtsev, Yu., E-mail: yuri.kudryavtsev@fys.kuleuven.be; Ferrer, R.; Huyse, M.; Van den Bergh, P.; Van Duppen, P. [Instituut voor Kern- en Stralingsfysica, KU Leuven, 3001 Leuven (Belgium); Vermeeren, L. [SCK-CEN, Nuclear Research Centre, Boeretang 200, B-2400 Mol (Belgium)

    2014-02-15

    The in-gas laser ionization and spectroscopy technique has been developed at the Leuven isotope separator on-line facility for the production and in-source laser spectroscopy studies of short-lived radioactive isotopes. In this article, results from a study to identify efficient optical schemes for the two-step resonance laser ionization of 18 elements are presented.

  20. First application of the Laser Ion Source and Trap (LIST) for on-line experiments at ISOLDE

    CERN Document Server

    Fink, D A; Imai, N; Blaum, K; Rothe, S; Sjoedin, M; Rossel, R E; Kron, T; Marsh, B A; Richter, S D; Cocolios, T E; Lecesne, N; Ghys, L; Pauwels, D; Rapisarda, E; Seliverstov, M D; Stora, T; Ramos, J P; Mendonca, T M; Fedosseev, V N; Lynch, K M; Wendt, K D A; Gottberg, A; Flanagan, K T; Van Beveren, C; Bastin, B; Fedorov, D V

    2013-01-01

    The Laser Ion Source and Trap (LIST) provides a new mode of operation for the resonance ionization laser ion source (RILIS) at ISOLDE/CERN, reducing the amount of surface-ionized isobaric contaminants by up to four orders of magnitude. After the first successful on-line test at ISOLDE in 2011 the LIST was further improved in terms of efficiency, selectivity, and reliability through several off-line tests at Mainz University and at ISOLDE. In September 2012, the first on-line physics experiments to use the LIST took place at ISOLDE. The measurements of the improved LIST indicate more than a twofold increase in efficiency compared to the LIST of the 2011 run. The suppression of surface-ionized francium contaminants has enabled the first in-source laser spectroscopy of Po-217 and Po-219. (C) 2013 Elsevier B.V. All rights reserved.

  1. 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...... for on-line monitoring if corrections or preventive measures during the quantification are carried out. The findings presented in this thesis have enabled the possibility of obtaining a better process understanding and to ease monitoring and controlling of fermentation processes....

  2. On-line characterization of YBCO coated conductors using Raman spectroscopy methods.

    Science.gov (United States)

    Maroni, V A; Reeves, J L; Schwab, G

    2007-04-01

    The use of Raman spectroscopy for on-line monitoring of the production of superconducting YBa2Cu3O6+X (YBCO) thin films on long-length metal tapes coated with textured buffer layers is reported for the first time. A methodology is described for obtaining Raman spectra of YBCO on moving tape exiting a metal-organic-chemical-vapor-deposition (MOCVD) enclosure. After baseline correction, the spectra recorded in this way show the expected phonons of the specific YBCO crystal orientation required for high supercurrent transport, as well as phonons of non-superconducting second-phase impurities when present. It is also possible to distinguish YBCO films that are properly textured from films having domains of misoriented YBCO grains. An investigation of the need for focus control on moving tape indicated that focusing of the laser on the surface of the highly reflective YBCO films exiting the MOCVD enclosure tends to produce aberrant photon bursts that swamp the Raman spectrum. These photon bursts are very likely a consequence of optical speckle effects induced by a combination of surface roughness, crystallographic texture, and/or local strain within the small grain microstructure of the YBCO film. Maintaining a slightly out-of-focus condition provides the best signal-to-noise ratio in terms of the obtained Raman spectra. In addition to examining moving tape at the post-MOCVD stage, Raman spectra of the film surface can also be recorded after the oxygen anneal performed to bring the YBCO to the optimum superconducting state. Consideration is given to data processing methods that could be adapted to the on-line Raman spectra to allow the tagging of out-of-specification tape segments and, at a more advanced level, feedback control to the MOCVD process.

  3. On-Line Wavelength Calibration of Pulsed Laser for CO2 Differential Absorption LIDAR

    Science.gov (United States)

    Xiang, Chengzhi; Ma, Xin; Han, Ge; Liang, Ailin; Gong, Wei

    2016-06-01

    Differential absorption lidar (DIAL) remote sensing is a promising technology for atmospheric CO2 detection. However, stringent wavelength accuracy and stability are required in DIAL system. Accurate on-line wavelength calibration is a crucial procedure for retrieving atmospheric CO2 concentration using the DIAL, particularly when pulsed lasers are adopted in the system. Large fluctuations in the intensities of a pulsed laser pose a great challenge for accurate on-line wavelength calibration. In this paper, a wavelength calibration strategy based on multi-wavelength scanning (MWS) was proposed for accurate on-line wavelength calibration of a pulsed laser for CO2 detection. The MWS conducted segmented sampling across the CO2 absorption line with appropriate number of points and range of widths by using a tunable laser. Complete absorption line of CO2 can be obtained through a curve fitting. Then, the on-line wavelength can be easily found at the peak of the absorption line. Furthermore, another algorithm called the energy matching was introduced in the MWS to eliminate the backlash error of tunable lasers during the process of on-line wavelength calibration. Finally, a series of tests was conducted to elevate the calibration precision of MWS. Analysis of tests demonstrated that the MWS proposed in this paper could calibrate the on-line wavelength of pulsed laser accurately and steadily.

  4. Laser Spectroscopy : XII International Conference

    CERN Document Server

    Allegrini, Maria; Sasso, Antonio

    1996-01-01

    This text includes all the recent advances in the field of laser spectroscopy. Major results span from the control of matter by electromagnetic fields (trapping and coding) to high precision measurements on simple atomic systems and to quantum optics with single atoms. It includes a report of the Bose-Einstein condensation achieved by laser-cooling of rubidium atoms. Achievements in the technology of tunable sources, in particular of miniaturized solid state devices, are also reported. Most recent advances in molecular spectroscopy are illustrated with emphasis on "cooled" spectra, clusters and high accuracy frequency references. Topics such as atomic interferometry and microcavity quantum optics are also covered.

  5. First application of the Laser Ion Source and Trap (LIST) for on-line experiments at ISOLDE

    Energy Technology Data Exchange (ETDEWEB)

    Fink, D.A., E-mail: daniel.fink@cern.ch [CERN, 1211 Geneva 23 (Switzerland); Max-Planck-Institut für Kernphysik, 69117 Heidelberg (Germany); Fakultät für Physik und Astronomie, Ruprecht-Karls Universität, 69120 Heidelberg (Germany); Richter, S.D. [Insitut für Physik, Johannes Gutenberg-Universität, 55122 Mainz (Germany); Bastin, B. [Grand Accélérateur National d’Ions Lourds (GANIL), Bd Henri Becquerel, F-14076 Caen (France); Blaum, K. [Max-Planck-Institut für Kernphysik, 69117 Heidelberg (Germany); Catherall, R. [CERN, 1211 Geneva 23 (Switzerland); Cocolios, T.E. [CERN, 1211 Geneva 23 (Switzerland); University of Manchester, Manchester M13 9PL (United Kingdom); Fedorov, D.V. [PNPI NRC KI, 188300 Orlova Roscha, Gatchina (Russian Federation); Fedosseev, V.N. [CERN, 1211 Geneva 23 (Switzerland); Flanagan, K.T. [University of Manchester, Manchester M13 9PL (United Kingdom); Ghys, L. [IKS KU Leuven, Celestijnenlkn 200D, B-3001 Leuven (Belgium); Belgian Nuclear Research Centre SCK-CEN, Boeretang 200, B-2400 Mol (Belgium); Gottberg, A. [CERN, 1211 Geneva 23 (Switzerland); Instituto de Estructura de la Materia, CSIC, 28006 Madrid (Spain); Imai, N. [High Energy Accelerator Research Organization (KEK), Oho 1-1, Tsukuba, Ibaraki 305-0801 (Japan); Kron, T. [Insitut für Physik, Johannes Gutenberg-Universität, 55122 Mainz (Germany); Lecesne, N. [Grand Accélérateur National d’Ions Lourds (GANIL), Bd Henri Becquerel, F-14076 Caen (France); and others

    2013-12-15

    Highlights: • First application of LIST target for on-line experiments at ISOLDE. • Reliable operation of LIST together with a strongly outgassing UCx target. • Suppression of isobaric contaminants by a factor of more than 10000 achieved. • Laser ionization efficiency of LIST improved by factor 2.5 compared to 2011 LIST. -- Abstract: The Laser Ion Source and Trap (LIST) provides a new mode of operation for the resonance ionization laser ion source (RILIS) at ISOLDE/CERN, reducing the amount of surface-ionized isobaric contaminants by up to four orders of magnitude. After the first successful on-line test at ISOLDE in 2011 the LIST was further improved in terms of efficiency, selectivity, and reliability through several off-line tests at Mainz University and at ISOLDE. In September 2012, the first on-line physics experiments to use the LIST took place at ISOLDE. The measurements of the improved LIST indicate more than a twofold increase in efficiency compared to the LIST of the 2011 run. The suppression of surface-ionized francium contaminants has enabled the first in-source laser spectroscopy of {sup 217}Po and {sup 219}Po.

  6. Discrimination of industrial products by on-line near infrared spectroscopy with an improved dendrogram

    Institute of Scientific and Technical Information of China (English)

    Jing Jing Liu; Heng Xu; Wen Sheng Cai; Xue Guang Shao

    2011-01-01

    Near infrared (NIR) spectroscopy technique has shown great power and gained wide acceptance for analyzing complicated samples. The present work is to distinguish different brands of tobacco products by using on-line NIR spectroscopy and pattern recognition techniques. Moreover, since each brand contains a large number of samples, an improved dendrogram was proposed to show the classification of different brands. The results suggest that MR spectroscopy combined with principal component analysis (PCA) and hierarchical cluster analysis (HCA) performs well in discrimination of the different brands, and the improved dendrogram could provide more information about the difference of the brands.

  7. The Resonance Ionization Laser Ion Source RILIS - leading all-rounder of on-line ion sources

    Energy Technology Data Exchange (ETDEWEB)

    Rothe, Sebastian [CERN, Geneva (Switzerland); Institut fuer Physik, Univ. Mainz (Germany); Fedosseev, Valentin; Fink, Daniel; Seliverstov, Maxim [CERN, Geneva (Switzerland); Rossel, Ralf [CERN, Geneva (Switzerland); Institut fuer Physik, Univ. Mainz (Germany); Hochschule RheinMain, Wiesbaden (Germany); Wendt, Klaus [Institut fuer Physik, Univ. Mainz (Germany)

    2012-07-01

    The resonance ionization laser ion source (RILIS) of the on-line isotope separator facility ISOLDE at CERN, is based on the method of stepwise resonant laser excitation and ionization of atoms. The element selectivity of the RILIS complements the mass selection process of the ISOLDE separator magnets to provide high purity ion beams of many isotopes. The RILIS, which now includes two complementary and independent tunable laser systems (dye and titanium:sapphire lasers), has been significantly improved since its first demonstration of selective ionization of Yb isotopes in 1992. Today, on account of the high degree of selectivity for the 27 elements now offered, the annual operation of RILIS exceeds 2500 h, making it the most versatile and commonly used ion source at ISOLDE. The use of a narrow band dye laser enables precision in-source laser spectroscopy of isotope shifts and hyperfine structures of isotopes far from stability as well as the production of isomer pure beams as has been demonstrated for Ag, Cu, Pb, Bi, Po, and Tl. A recent upgrade of the RILIS comprises the incorporation of a complementary all solid state laser system as well as the Laser Ion Source Trap (LIST), which greatly enhances selectivity by suppressing any surface ionized isobars.

  8. Laser spectroscopy of cold molecules

    CERN Document Server

    Borri, Simone

    2016-01-01

    This paper reviews the recent results in high-resolution spectroscopy on cold molecules. Laser spectroscopy of cold molecules addresses issues of symmetry violation, like in the search for the electric dipole moment of the electron and the studies on energy differences in enantiomers of chiral species; tries to improve the precision to which fundamental physical constants are known and tests for their possible variation in time and space; tests quantum electrodynamics, and searches for a fifth force. Further, we briefly review the recent technological progresses in the fields of cold molecules and mid-infrared lasers, which are the tools that mainly set the limits for the resolution that is currently attainable in the measurements.

  9. Towards laser spectroscopy of antihydrogen

    Energy Technology Data Exchange (ETDEWEB)

    Walz, J [CERN-EP/APE, CH-1211 Geneve (Switzerland); Fendel, P [Max-Planck-Institut fuer Quantenoptik, Hans-Kopfermann-Strasse 1, D-85748 Garching (Germany); Herrmann, M [Max-Planck-Institut fuer Quantenoptik, Hans-Kopfermann-Strasse 1, D-85748 Garching (Germany); Koenig, M [Max-Planck-Institut fuer Quantenoptik, Hans-Kopfermann-Strasse 1, D-85748 Garching (Germany); Pahl, A [Max-Planck-Institut fuer Quantenoptik, Hans-Kopfermann-Strasse 1, D-85748 Garching (Germany); Pittner, H [Max-Planck-Institut fuer Quantenoptik, Hans-Kopfermann-Strasse 1, D-85748 Garching (Germany); Schatz, B [Max-Planck-Institut fuer Quantenoptik, Hans-Kopfermann-Strasse 1, D-85748 Garching (Germany); Haensch, T W [Max-Planck-Institut fuer Quantenoptik, Hans-Kopfermann-Strasse 1, D-85748 Garching (Germany)

    2003-02-14

    Cold antihydrogen atoms in a magnetic trap will open up a fascinating field of very precise CPT tests by ultrahigh-resolution laser spectroscopy. Equally exciting is the prospect for experiments on the gravitational acceleration of antimatter. For both types of experiment it is of great importance to have antihydrogen as cold as possible. Laser cooling of antihydrogen can be done on the strong 1S-2P transition at Lyman-{alpha} (121.56 nm). The highest cooling efficiency, lowest temperature, and best magnetic sublevel selectivity is expected for continuous coherent radiation. We present an account of the first source for continuous coherent radiation at Lyman-{alpha} and discuss possible applications in experiments with antihydrogen.

  10. Laser spectroscopy of atomic radium

    Energy Technology Data Exchange (ETDEWEB)

    Groot, Alexander; Jungmann, Klaus; Santra, Bodhaditya; Willmann, Lorenz; Wilschut, Hans W. [KVI, University of Groningen (Netherlands)

    2009-07-01

    The heavy alkaline earth elements radium (Ra) offers a unique sensitivity to a parity and time reversal violating permanent electric dipole moments (EDM). In particular, Ra exhibits the largest known atomic enhancements factors for EDMs. The intrinsic sensitivity arises from the specific atomic and nuclear structure of Ra. All Ra isotopes with nuclear spin I are radioactive. The lifetimes are shorter than 15 d. Several Ra isotopes are available at the TRI{mu}P facility at KVI. For the exploitation of the sensitivity Ra atoms have to be collected in a neutral atom trap. The main laser cooling is done on the strong {sup 1}S{sub 0}-{sup 1}P{sub 1} transition at 482.7 nm, similar to the laser cooling and trapping of the chemical homologue barium. Laser spectroscopy of the strong {sup 1}S{sub 0}-{sup 1}P{sub 1} transitions is presented. The light at this wavelength is provided by frequency doubling of a Ti:sapphire laser in a KNbO{sub 3} crystal. Of particular interest is the decay branching of the excited state to the metastable D-states. Such measurements are indispensable input for current atomic structure calculations, which are necessary for the analysis of a EDM measurement using Ra.

  11. On-line estimation of laser-drilled hole depth using a machine vision method.

    Science.gov (United States)

    Ho, Chao-Ching; He, Jun-Jia; Liao, Te-Ying

    2012-01-01

    The paper presents a novel method for monitoring and estimating the depth of a laser-drilled hole using machine vision. Through on-line image acquisition and analysis in laser machining processes, we could simultaneously obtain correlations between the machining processes and analyzed images. Based on the machine vision method, the depths of laser-machined holes could be estimated in real time. Therefore, a low cost on-line inspection system is developed to increase productivity. All of the processing work was performed in air under standard atmospheric conditions and gas assist was used. A correlation between the cumulative size of the laser-induced plasma region and the depth of the hole is presented. The result indicates that the estimated depths of the laser-drilled holes were a linear function of the cumulative plasma size, with a high degree of confidence. This research provides a novel machine vision-based method for estimating the depths of laser-drilled holes in real time.

  12. On-Line Estimation of Laser-Drilled Hole Depth Using a Machine Vision Method

    Directory of Open Access Journals (Sweden)

    Te-Ying Liao

    2012-07-01

    Full Text Available The paper presents a novel method for monitoring and estimating the depth of a laser-drilled hole using machine vision. Through on-line image acquisition and analysis in laser machining processes, we could simultaneously obtain correlations between the machining processes and analyzed images. Based on the machine vision method, the depths of laser-machined holes could be estimated in real time. Therefore, a low cost on-line inspection system is developed to increase productivity. All of the processing work was performed in air under standard atmospheric conditions and gas assist was used. A correlation between the cumulative size of the laser-induced plasma region and the depth of the hole is presented. The result indicates that the estimated depths of the laser-drilled holes were a linear function of the cumulative plasma size, with a high degree of confidence. This research provides a novel machine vision-based method for estimating the depths of laser-drilled holes in real time.

  13. Resonance ionization laser ion sources for on-line isotope separators (invited).

    Science.gov (United States)

    Marsh, B A

    2014-02-01

    A Resonance Ionization Laser Ion Source (RILIS) is today considered an essential component of the majority of Isotope Separator On Line (ISOL) facilities; there are seven laser ion sources currently operational at ISOL facilities worldwide and several more are under development. The ionization mechanism is a highly element selective multi-step resonance photo-absorption process that requires a specifically tailored laser configuration for each chemical element. For some isotopes, isomer selective ionization may even be achieved by exploiting the differences in hyperfine structures of an atomic transition for different nuclear spin states. For many radioactive ion beam experiments, laser resonance ionization is the only means of achieving an acceptable level of beam purity without compromising isotope yield. Furthermore, by performing element selection at the location of the ion source, the propagation of unwanted radioactivity downstream of the target assembly is reduced. Whilst advances in laser technology have improved the performance and reliability of laser ion sources and broadened the range of suitable commercially available laser systems, many recent developments have focused rather on the laser/atom interaction region in the quest for increased selectivity and/or improved spectral resolution. Much of the progress in this area has been achieved by decoupling the laser ionization from competing ionization processes through the use of a laser/atom interaction region that is physically separated from the target chamber. A new application of gas catcher laser ion source technology promises to expand the capabilities of projectile fragmentation facilities through the conversion of otherwise discarded reaction fragments into high-purity low-energy ion beams. A summary of recent RILIS developments and the current status of laser ion sources worldwide is presented.

  14. On-line reaction monitoring of lithiation of halogen substituted acetanilides via in situ calorimetry, ATR spectroscopy, and endoscopy.

    Science.gov (United States)

    Godany, Tamas A; Neuhold, Yorck-Michael; Hungerbühler, Konrad

    2011-01-01

    Lithiation of N-(4-chlorophenyl)-pivalamide (NCP) and two additional substituted acetanilides: 4-fluoroacetanilide (4-F) and 4-chloroacetanilide (4-Cl) has been monitored by means of calorimetry, on-line ATR-IR and UV/vis spectroscopy and endoscopy. The combined on-line monitoring revealed the differences between the reaction paths of the chosen substrates. Thus the product structure and the reaction times for the individual reaction steps can be determined in situ.

  15. Application of laser ultrasonic method for on-line monitoring of friction stir spot welding process.

    Science.gov (United States)

    Zhang, Kuanshuang; Zhou, Zhenggan; Zhou, Jianghua

    2015-09-01

    Application of a laser ultrasonic method is developed for on-line monitoring of the friction stir spot welding (FSSW) process. Based on the technology of FSSW, laser-generated ultrasonic waves in a good weld and nonweld area are simulated by a finite element method. The reflected and transmitted waves are analyzed to disclose the properties of the welded interface. The noncontact-laser ultrasonic-inspection system was established to verify the numerical results. The reflected waves in the good-weld and nonweld area can be distinguished by time-of-flight. The transmitted waves evidently attenuate in the nonweld area in contrast to signal amplitude in the good weld area because of interfacial impedance difference. Laser ultrasonic C-scan images can sufficiently evaluate the intrinsic character of the weld area in comparison with traditional water-immersion ultrasonic testing results. The research results confirm that laser ultrasonics would be an effective method to realize the characterization of FSSW defects.

  16. High-resolution in-source laser spectroscopy in perpendicular geometry

    Energy Technology Data Exchange (ETDEWEB)

    Heinke, R., E-mail: reinhard.heinke@uni-mainz.de; Kron, T. [Universität Mainz, Institut für Physik (Germany); Raeder, S. [Helmholtz-Institut Mainz (Germany); Reich, T.; Schönberg, P. [Universität Mainz, Institut für Kernchemie (Germany); Trümper, M.; Weichhold, C.; Wendt, K. [Universität Mainz, Institut für Physik (Germany)

    2017-11-15

    Operation of the novel laser ion source unit LIST (Laser Ion Source and Trap), operating at the on-line radioactive ion beam facility ISOLDE at CERN allowed for the production of ultra-pure beams of exotic isotopes far-off stability as well as direct isobar-free laser spectroscopy, giving access to the study of atomic and nuclear properties of so far inaccessible nuclides. We present a specific upgrade and adaption of the LIST targeted for high resolution spectroscopy with a Doppler-reduced perpendicular atom - laser beam geometry. With this PI-LIST (Perpendicularly Illuminated Laser Ion Source and Trap) setup, experimental linewidths below 100 MHz could be demonstrated in optical laser spectroscopy off-line, applying a pulsed injection-locked high repetition rate Ti:sapphire laser. A dual repeller configuration ensured highest suppression of isobaric interferences and almost background-free measurements on small samples in the order of 10{sup 11} atoms.

  17. On-line monitoring of chemical reactions by using bench-top nuclear magnetic resonance spectroscopy.

    Science.gov (United States)

    Danieli, E; Perlo, J; Duchateau, A L L; Verzijl, G K M; Litvinov, V M; Blümich, B; Casanova, F

    2014-10-06

    Real-time nuclear magnetic resonance (NMR) spectroscopy measurements carried out with a bench-top system installed next to the reactor inside the fume hood of the chemistry laboratory are presented. To test the system for on-line monitoring, a transfer hydrogenation reaction was studied by continuously pumping the reaction mixture from the reactor to the magnet and back in a closed loop. In addition to improving the time resolution provided by standard sampling methods, the use of such a flow setup eliminates the need for sample preparation. Owing to the progress in terms of field homogeneity and sensitivity now available with compact NMR spectrometers, small molecules dissolved at concentrations on the order of 1 mmol L(-1) can be characterized in single-scan measurements with 1 Hz resolution. Owing to the reduced field strength of compact low-field systems compared to that of conventional high-field magnets, the overlap in the spectrum of different NMR signals is a typical situation. The data processing required to obtain concentrations in the presence of signal overlap are discussed in detail, methods such as plain integration and line-fitting approaches are compared, and the accuracy of each method is determined. The kinetic rates measured for different catalytic concentrations show good agreement with those obtained with gas chromatography as a reference analytical method. Finally, as the measurements are performed under continuous flow conditions, the experimental setup and the flow parameters are optimized to maximize time resolution and signal-to-noise ratio.

  18. Agent-based station for on-line diagnostics by self-adaptive laser Doppler vibrometry

    Science.gov (United States)

    Serafini, S.; Paone, N.; Castellini, P.

    2013-12-01

    A self-adaptive diagnostic system based on laser vibrometry is proposed for quality control of mechanical defects by vibration testing; it is developed for appliances at the end of an assembly line, but its characteristics are generally suited for testing most types of electromechanical products. It consists of a laser Doppler vibrometer, equipped with scanning mirrors and a camera, which implements self-adaptive bahaviour for optimizing the measurement. The system is conceived as a Quality Control Agent (QCA) and it is part of a Multi Agent System that supervises all the production line. The QCA behaviour is defined so to minimize measurement uncertainty during the on-line tests and to compensate target mis-positioning under guidance of a vision system. Best measurement conditions are reached by maximizing the amplitude of the optical Doppler beat signal (signal quality) and consequently minimize uncertainty. In this paper, the optimization strategy for measurement enhancement achieved by the down-hill algorithm (Nelder-Mead algorithm) and its effect on signal quality improvement is discussed. Tests on a washing machine in controlled operating conditions allow to evaluate the efficacy of the method; significant reduction of noise on vibration velocity spectra is observed. Results from on-line tests are presented, which demonstrate the potential of the system for industrial quality control.

  19. Resonance ionization spectroscopy using ultraviolet laser

    CERN Document Server

    Han, J M; Ko, D K; Park, H M; Rhee, Y J

    2002-01-01

    In this study, Ti:sapphire laser which is pumped by the enhanced Nd:YAG laser using laser diode, was designed and manufactured. The AO Q-switched CW Nd:YAG laser was converted into a high repetition plus-type laser using the AO Q-switch, and two heads were installed inside the cavity in order to improve the laser beam quality. The Nd:YAG laser enhancement was completed by optimization using a simulation for the cavity length, structure and thermal lens effect that greatly effected the laser beam output and quality. As the result of the enhancement, a 30W laser at 532nm and at 5k-Hz was successfully made. Also, the Ti:sapphire laser that will be used for atomic spectroscopy which is pumped by the Nd:YAG laser, was completely designed. As a basic experiment for laser oscillation. We measured the tunability of the laser, and it turned out that the wave tunability range was 730 850 nm. A self-seeding type tunable laser using grating for narrow line width, is planned to be designed due to the fact that the Ti:sapp...

  20. Simulated 'On-Line' Wear Metal Analysis of Lubricating Oils by X-Ray Fluorescence Spectroscopy

    Science.gov (United States)

    Kelliher, Warren C.; Partos, Richard D.; Nelson, Irina

    1996-01-01

    The objective of this project was to assess the sensitivity of X-ray Fluorescence Spectroscopy (XFS) for quantitative evaluation of metal particle content in engine oil suspensions and the feasibility of real-time, dynamic wear metal analysis. The study was focused on iron as the majority wear metal component. Variable parameters were: particle size, particle concentration and oil velocity. A commercial XFS spectrometer equipped with interchangeable static/dynamic (flow cell) sample chambers was used. XFS spectra were recorded for solutions of Fe-organometallic standard and for a series of DTE oil suspensions of high purity spherical iron particles of 2g, 4g, and 8g diameter, at concentrations from 5 ppm to 5,000 ppm. Real contaminated oil samples from Langley Air Force Base aircraft engines and NASA Langley Research Center wind tunnels were also analyzed. The experimental data conform the reliability of XFS as the analytical method of choice for this project. Intrinsic inadequacies of the instrument for precise analytic work at low metal concentrations were identified as being related to the particular x-ray beam definition, system geometry, and flow-cell materials selection. This work supports a proposal for the design, construction and testing of a conceptually new, miniature XFS spectrometer with superior performance, dedicated to on-line, real-time monitoring of lubricating oils in operating engines. Innovative design solutions include focalization of the incident x-ray beam, non-metal sample chamber, and miniaturization of the overall assembly. The instrument would contribute to prevention of catastrophic engine failures. A proposal for two-year funding has been presented to NASA Langley Research Center Internal Operation Group (IOG) Management, to continue the effort begun by this summer's project.

  1. Development of an Ionization Scheme for Gold using the Selective Laser Ion Source at the On-Line Isotope Separator ISOLDE

    CERN Document Server

    Fedosseev, V; Marsh, B A; CERN. Geneva. AB Department

    2006-01-01

    At the ISOLDE on-line isotope separation facility, the resonance ionization laser ion source (RILIS) can be used to ionize reaction products as they effuse from the target. The RILIS process of laser step-wise resonance ionization of atoms in a hot metal cavity provides a highly element selective stage in the preparation of the radioactive ion beam. As a result, the ISOLDE mass separators can provide beams of a chosen isotope with greatly reduced isobaric contamination. The number of elements available at RILIS has been extended to 26, with the addition of a new three-step ionization scheme for gold. The optimal ionization scheme was determined during an extensive study of the atomic energy levels and auto-ionizing states of gold, carried out by means of in-source resonance ionization spectroscopy. Details of the ionization scheme and a summary of the spectroscopy study are presented.

  2. On-line monitoring of one-step laser fabrication of micro-optical components.

    Science.gov (United States)

    Juliá, J E; Soriano, J C

    2001-07-01

    The use of an on-line monitoring method based on photoelasticity techniques for the fabrication of micro-optical components by means of controlled laser heating is described. From this description it is possible to show in real time the mechanical stresses that form the microelement. A new parameter, stressed area, is introduced that quantifies the stresses of a microelement during its fabrication, facilitating a deeper understanding of the physical phenomena involved in the process as well as being a useful test of quality. It also permits the stress produced in the manufacturing process and the optical properties of the final microelement to be correlated. The results for several microlenses monitored with this technique are presented.

  3. [Applications and prospects of on-line near infrared spectroscopy technology in manufacturing of Chinese materia medica].

    Science.gov (United States)

    Li, Yang; Wu, Zhi-Sheng; Pan, Xiao-Ning; Shi, Xin-Yuan; Guo, Ming-Ye; Xu, Bing; Qiao, Yan-Jiang

    2014-10-01

    The quality of Chinese materia medica (CMM) is affected by every process in CMM manufacturing. According to multi-unit complex features in the production of CMM, on-line near infrared spectroscopy (NIR) is used as an evaluating technology with its rapid, non-destructive and non-pollution etc. advantages. With the research in institutions, the on-line NIR applied in process analysis and control of CMM was described systematically, and the on-line NIR platform building was used as an example to clarify the feasibility of on-line NIR technology in CMM manufacturing process. Then, from the point of application by pharmaceutical companies, the current on-line NIR research on CMM and its production in pharmaceutical companies was relatively comprehensively summarized. Meanwhile, the types of CMM productions were classified in accordance with two formulations (liquid and solid dosage formulations). The different production processes (extraction, concentration and alcohol precipitation, etc. ) were used as liquid formulation diacritical points; the different types (tablets, capsules and plasters, etc.) were used as solid dosage formulation diacritical points, and the reliability of on-line NIR used in the whole process in CMM production was proved in according to the summary of literatures in recent 10 years, which could support the modernization of CMM production.

  4. Photon Correlation Spectroscopy for Observing Natural Lasers

    CERN Document Server

    Dravins, Dainis

    2007-01-01

    Natural laser emission may be produced whenever suitable atomic energy levels become overpopulated. Strong evidence for laser emission exists in astronomical sources such as Eta Carinae, and other luminous stars. However, the evidence is indirect in that the laser lines have not yet been spectrally resolved. The lines are theoretically estimated to be extremely narrow, requiring spectral resolutions very much higher (R approx.= 10**8) than possible with ordinary spectroscopy. Such can be attained with photon-correlation spectroscopy on nanosecond timescales, measuring the autocorrelation function of photon arrival times to obtain the coherence time of light, and thus the spectral linewidth. A particular advantage is the insensitivity to spectral, spatial, and temporal shifts of emission-line components due to local velocities and probable variability of 'hot-spots' in the source. A laboratory experiment has been set up, simulating telescopic observations of cosmic laser emission. Numerically simulated observa...

  5. Plasma spectroscopy using optical vortex laser

    Science.gov (United States)

    Yoshimura, Shinji; Aramaki, Mitsutoshi; Terasaka, Kenichiro; Toda, Yasunori; Czarnetzki, Uwe; Shikano, Yutaka

    2014-10-01

    Laser spectroscopy is a useful tool for nonintrusive plasma diagnostics; it can provide many important quantities in a plasma such as temperature, density, and flow velocity of ions and neutrals from the spectrum obtained by scanning the frequency of narrow bandwidth laser. Obtainable information is, however, limited in principle to the direction parallel to the laser path. The aim of this study is to introduce a Laguerre-Gaussian beam, which is called as optical vortex, in place of a widely used Hermite-Gaussian beam. One of the remarkable properties of the Laguerre-Gaussian beam is that it carries an angular momentum in contrast to the Hermite-Gaussian beam. It follows that particles in the laser beam feel the Doppler effect even in the transverse direction of the laser path. Therefore it is expected that the limitation imposed by the laser path can be overcome by using an optical vortex laser. The concept of optical vortex spectroscopy, the development of the laser system, and some preliminary results of a proof-of-principle experiment will be presented. This work is performed with the support and under the auspices of NINS young scientists collaboration program for cross-disciplinary study, NIFS collaboration research program (NIFS13KOAP026), and JSPS KAKENHI Grant Number 25287152.

  6. Quality control agent: Self-adaptive laser vibrometry for on-line diagnostics

    Science.gov (United States)

    Serafini, S.; Paone, N.; Castellini, P.

    2012-06-01

    It is presented the development of a self-adaptive diagnostic system based on laser vibrometry for production line quality control. The vibration measurement system consists of a laser Doppler vibrometer, equipped with scanning mirrors and a smart camera, which implements self-adaptivity for compensating target mis-positioning under guidance by a vision system and for the achievement of the best condition for measurement by optimizing the Doppler signal level. This system is designed as a Quality Control Agent (QCA) and it is part of a Multi Agent System (MAS) that supervises all the production line. The QCA behavior is defined so to perform a minimization of measurement uncertainty during the on line tests; for this purpose the QCA exhibits a self-adaptive behavior. Best measurement conditions are defined in terms of amplitude of the optical Doppler beat signal (signal quality - SQ). In this paper, the optimization strategy for measurement enhancement achieved by the down-hill algorithm (Nelder-Mead algorithm) and its effect on signal quality improvement is discussed. Tests on a washing machine in controlled operating conditions allow to evaluate the efficacy of the method; significant reduction of noise on vibration velocity spectra is observed.

  7. Digital signal processor-based high-precision on-line Voigt lineshape fitting for direct absorption spectroscopy.

    Science.gov (United States)

    Xu, Lijun; Liu, Chang; Zheng, Deyan; Cao, Zhang; Cai, Weiwei

    2014-12-01

    To realize on-line high-accuracy measurement in direct absorption spectroscopy (DAS), a system-on-chip, high-precision digital signal processor-based on-line Voigt lineshape fitting implementation is introduced in this paper. Given that the Voigt lineshape is determined by the Gauss full width at half maximum (FWHM) and Lorentz FWHM, a look-up table, which covers a range of combinations of both, is first built to achieve rapid and accurate calculation of Voigt lineshape. With the look-up table and raw absorbance data in hand, Gauss-Newton nonlinear fitting module is implemented to obtain the parameters including both the Gauss and Lorentz FWHMs, which can be used to calculate the integrated absorbance. To realize the proposed method in hardware, a digital signal processor (DSP) is adopted to fit the Voigt lineshape in a real-time DAS measurement system. In experiment, temperature and H2O concentration of a flat flame are recovered from the transitions of 7444.36 cm(-1) and 7185.6 cm(-1) by the DSP-based on-line Voigt lineshape fitting and on-line integral of the raw absorbance, respectively. The results show that the proposed method can not only fit the Voigt lineshape on-line but also improve the measurement accuracy compared with those obtained from the direct integral of the raw absorbance.

  8. Diamond: a material for laser spectroscopy

    Science.gov (United States)

    Castex, M. C.; Riedel, D.; Museur, L.; Chardonnet, Christian; Gicquel, Alix; Foulon, Francois; Borel, C.; Bergonzo, P.; Jany, C.

    1998-10-01

    Diamond polycrystalline films synthesized by chemical vapor deposition techniques present interesting feature for laser spectroscopy due to several advantages arising from their optical, electronic, thermal and mechanical properties. Their wide transmission band from the far IR to the UV make them attractive as optical devices for high-power laser beam. Moreover, with a wide band gap, a short carrier lifetime and a high damage threshold, diamond is an ideal semiconductor material for the fabrication of fast and solar blind VUV detectors. We report here results of laser studies performed with tow different objectives. With use of a pulsed VUV laser at 125 nm we have determined the photoconductive response of polycrystalline diamond detectors. With a CO2 laser we have investigated the polarization properties of auto-supported films having thicknesses smaller than the wavelength.

  9. Laser spectroscopy and dynamics of transient species

    Energy Technology Data Exchange (ETDEWEB)

    Clouthier, D.J. [Univ. of Kentucky, Lexington (United States)

    1993-12-01

    The goal of this program is to study the vibrational and electronic spectra and excited state dynamics of a number of transient sulfur and oxygen species. A variety of supersonic jet techniques, as well as high resolution FT-IR and intracavity dye laser spectroscopy, have been applied to these studies.

  10. Laser photoelectron spectroscopy of ions

    Energy Technology Data Exchange (ETDEWEB)

    Ellison, G.B. [Univ. of Colorado, Boulder (United States)

    1993-12-01

    During the last year the author has (a) completed a review article that critically contrasts three methods to measure R-H bond energies, (b) finished a spectroscopic study of the phenylnitrene anion, and (c) successfully completed an overhaul of the light source of the photodetachment spectrometer. The new light source is based on an Ar III laser that provides approximately 100 W of 3.531 eV photons.

  11. Application of on-line NIR spectroscopy in fuel pellet production

    Energy Technology Data Exchange (ETDEWEB)

    Grothage, Morgan; Svensson, Elin; Johnsson, Bo [Casco Adhesives AB, Sundsvall (Sweden); Lestander, Torbjoern A. [Swedish Univ of Agricultural Science, Umeaa (Sweden). Unit of Biomass Technology and Chemistry

    2006-07-15

    Different possibilities of installation of on-line NIR spectrometers in various process environments in the fuel Pellets process were investigated using moisture content on dried wood raw material as the model analyte. Scanning NIR instruments of different types and to some extent diode-array instrument were used. Real time predictions of moisture content from partial least squares regression models were presented to the process operators using dedicated software.

  12. On-line depth measurement for laser-drilled holes based on the intensity of plasma emission

    Science.gov (United States)

    Ho, Chao-Ching; Chiu, Chih-Mu; Chang, Yuan-Jen; Hsu, Jin-Chen; Kuo, Chia-Lung

    2014-09-01

    The direct time-resolved depth measurement of blind holes is extremely difficult due to the short time interval and the limited space inside the hole. This work presents a method that involves on-line plasma emission acquisition and analysis to obtain correlations between the machining processes and the optical signal output. Given that the depths of laser-machined holes can be estimated on-line using a coaxial photodiode, this was employed in our inspection system. Our experiments were conducted in air under normal atmospheric conditions without gas assist. The intensity of radiation emitted from the vaporized material was found to correlate with the depth of the hole. The results indicate that the estimated depths of the laser-drilled holes were inversely proportional to the maximum plasma light emission measured for a given laser pulse number.

  13. On-line monitoring of the transesterification reaction between triglycerides and ethanol using near infrared spectroscopy combined with gas chromatography.

    Science.gov (United States)

    Richard, Romain; Li, Ying; Dubreuil, Brigitte; Thiebaud-Roux, Sophie; Prat, Laurent

    2011-06-01

    Many analytical procedures have been developed to determine the composition of reaction mixtures during transesterification of vegetable oils with alcohols. However, despite their accuracy, these methods are time consuming and cannot be easily used for on-line monitoring. In this work, a fast analytical method was developed to on-line monitor the transesterification reaction of high oleic sunflower oil with ethanol using Near InfraRed spectroscopy and a multivariate approach. The reactions were monitored through sequential scans of the reaction medium with a probe in a one-liter batch reactor without collecting and preparing samples. To calibrate the NIR analytical method, gas chromatography-flame ionization detection was used as a reference method. The method was validated by studying the kinetics of the EtONa-catalyzed transesterification reaction. Activation energy (51.0 kJ/mol) was also determined by considering a pseudo second order kinetics model. Copyright © 2011 Elsevier Ltd. All rights reserved.

  14. In-source laser spectroscopy of polonium isotopes: From atomic physics to nuclear structure

    CERN Multimedia

    Rothe, S

    2014-01-01

    The Resonance Ionization Laser Ion Source RILIS [1] at the CERN-ISOLDE on-line radioactive ion beam facility is essential for ion beam production for the majority of experiments, but it is also powerful tool for laser spectroscopy of rare isotopes. A series of experiments on in-source laser spectroscopy of polonium isotopes [2, 3] revealed the nuclear ground state properties of 191;211;216;218Po. However, limitations caused by the isobaric background of surface-ionized francium isotopes hindered the study of several neutron rich polonium isotopes. The development of the Laser Ion Source and Trap (LIST) [4] and finally its integration at ISOLDE has led to a dramatic suppression of surface ions. Meanwhile, the RILIS laser spectroscopy capabilities have advanced tremendously. Widely tunable titanium:sapphire (Ti:Sa) lasers were installed to complement the established dye laser system. Along with a new data acquisition system [5], this more versatile laser setup enabled rst ever laser spectroscopy of the radioact...

  15. Laser-induced breakdown spectroscopy in Asia

    Science.gov (United States)

    Wang, Zhen-Zhen; Deguchi, Yoshihiro; Zhang, Zhen-Zhen; Wang, Zhe; Zeng, Xiao-Yan; Yan, Jun-Jie

    2016-12-01

    Laser-induced breakdown spectroscopy (LIBS) is an analytical detection technique based on atomic emission spectroscopy to measure the elemental composition. LIBS has been extensively studied and developed due to the non-contact, fast response, high sensitivity, real-time and multi-elemental detection features. The development and applications of LIBS technique in Asia are summarized and discussed in this review paper. The researchers in Asia work on different aspects of the LIBS study in fundamentals, data processing and modeling, applications and instrumentations. According to the current research status, the challenges, opportunities and further development of LIBS technique in Asia are also evaluated to promote LIBS research and its applications.

  16. Developments towards in-gas-jet laser spectroscopy studies of actinium isotopes at LISOL

    Energy Technology Data Exchange (ETDEWEB)

    Raeder, S., E-mail: s.raeder@gsi.de [KU Leuven, Instituut voor Kern- en Stralingsfysica, Celestijnenlaan 200D, B-3001 Leuven (Belgium); Helmholtz-Institut Mainz, 55128 Mainz (Germany); GSI Helmholtzzentrum für Schwerionenforschung GmbH, Planckstraße 1, 64291 Darmstadt (Germany); Bastin, B. [GANIL, CEA/DSM-CNRS/IN2P3, B.P. 55027, 14076 Caen (France); Block, M. [Helmholtz-Institut Mainz, 55128 Mainz (Germany); GSI Helmholtzzentrum für Schwerionenforschung GmbH, Planckstraße 1, 64291 Darmstadt (Germany); Institut für Kernchemie, Johannes Gutenberg Universität, 55128 Mainz (Germany); Creemers, P. [KU Leuven, Instituut voor Kern- en Stralingsfysica, Celestijnenlaan 200D, B-3001 Leuven (Belgium); Delahaye, P. [GANIL, CEA/DSM-CNRS/IN2P3, B.P. 55027, 14076 Caen (France); Ferrer, R. [KU Leuven, Instituut voor Kern- en Stralingsfysica, Celestijnenlaan 200D, B-3001 Leuven (Belgium); Fléchard, X. [LPC Caen, ENSICAEN, Université de Caen, CNRS/IN2P3, Caen (France); Franchoo, S. [Institute de Physique Nucléaire (IPN) d’Orsay, 91406 Orsay, Cedex (France); Ghys, L. [KU Leuven, Instituut voor Kern- en Stralingsfysica, Celestijnenlaan 200D, B-3001 Leuven (Belgium); SCK-CEN, Belgian Nuclear Research Center, Boeretang 200, 2400 Mol (Belgium); Gaffney, L.P.; Granados, C. [KU Leuven, Instituut voor Kern- en Stralingsfysica, Celestijnenlaan 200D, B-3001 Leuven (Belgium); Heinke, R. [Institut für Physik, Johannes Gutenberg Universität, 55128 Mainz (Germany); Hijazi, L. [GANIL, CEA/DSM-CNRS/IN2P3, B.P. 55027, 14076 Caen (France); and others

    2016-06-01

    To study exotic nuclides at the borders of stability with laser ionization and spectroscopy techniques, highest efficiencies in combination with a high spectral resolution are required. These usually opposing requirements are reconciled by applying the in-gas-laser ionization and spectroscopy (IGLIS) technique in the supersonic gas jet produced by a de Laval nozzle installed at the exit of the stopping gas cell. Carrying out laser ionization in the low-temperature and low density supersonic gas jet eliminates pressure broadening, which will significantly improve the spectral resolution. This article presents the required modifications at the Leuven Isotope Separator On-Line (LISOL) facility that are needed for the first on-line studies of in-gas-jet laser spectroscopy. Different geometries for the gas outlet and extraction ion guides have been tested for their performance regarding the acceptance of laser ionized species as well as for their differential pumping capacities. The specifications and performance of the temporarily installed high repetition rate laser system, including a narrow bandwidth injection-locked Ti:sapphire laser, are discussed and first preliminary results on neutron-deficient actinium isotopes are presented indicating the high capability of this novel technique.

  17. Laser Spectroscopy of Muonic Atoms and Ions

    CERN Document Server

    Pohl, Randolf; Fernandes, Luis M P; Ahmed, Marwan Abdou; Amaro, Fernando D; Amaro, Pedro; Biraben, François; Cardoso, João M R; Covita, Daniel S; Dax, Andreas; Dhawan, Satish; Diepold, Marc; Franke, Beatrice; Galtier, Sandrine; Giesen, Adolf; Gouvea, Andrea L; Götzfried, Johannes; Graf, Thomas; Hänsch, Theodor W; Hildebrandt, Malte; Indelicato, Paul; Julien, Lucile; Kirch, Klaus; Knecht, Andreas; Knowles, Paul; Kottmann, Franz; Krauth, Julian J; Bigot, Eric-Olivier Le; Liu, Yi-Wei; Lopes, José A M; Ludhova, Livia; Machado, Jorge; Monteiro, Cristina M B; Mulhauser, Françoise; Nebel, Tobias; Rabinowitz, Paul; Santos, Joaquim M F dos; Santos, José Paulo; Schaller, Lukas A; Schuhmann, Karsten; Schwob, Catherine; Szabo, Csilla I; Taqqu, David; Veloso, João F C A; Voss, Andreas; Weichelt, Birgit; Antognini, Aldo

    2016-01-01

    Laser spectroscopy of the Lamb shift (2S-2P energy difference) in light muonic atoms or ions, in which one negative muon $\\mu^-$ is bound to a nucleus, has been performed. The measurements yield significantly improved values of the root-mean-square charge radii of the nuclei, owing to the large muon mass, which results in a vastly increased muon wave function overlap with the nucleus. The values of the proton and deuteron radii are 10 and 3 times more accurate than the respective CODATA values, but 7 standard deviations smaller. Data on muonic helium-3 and -4 ions is being analyzed and will give new insights. In future, the (magnetic) Zemach radii of the proton and the helium-3 nuclei will be determined from laser spectroscopy of the 1S hyperfine splittings, and the Lamb shifts of muonic Li, Be and B can be used to improve the respective charge radii.

  18. Laser-Induced Breakdown Spectroscopy in Africa

    Directory of Open Access Journals (Sweden)

    M. A. Kasem

    2015-01-01

    Full Text Available Laser-induced breakdown spectroscopy (LIBS, known also as laser-induced plasma spectroscopy (LIPS, is a well-known spectrochemical elemental analysis technique. The field of LIBS has been rapidly matured as a consequence of growing interest in real-time analysis across a broad spectrum of applied sciences and recent development of commercial LIBS analytical systems. In this brief review, we introduce the contributions of the research groups in the African continent in the field of the fundamentals and applications of LIBS. As it will be shown, the fast development of LIBS in Africa during the last decade was mainly due to the broad environmental, industrial, archaeological, and biomedical applications of this technique.

  19. Laser induced breakdown spectroscopy on meteorites

    Energy Technology Data Exchange (ETDEWEB)

    De Giacomo, A. [Department of Chemistry, University of Bari (Italy); MIP-CNR sec Bari (Italy)], E-mail: alessandro.degiacomo@ba.imip.cnr.it; Dell' Aglio, M.; De Pascale, O. [MIP-CNR sec Bari (Italy); Longo, S.; Capitelli, M. [Department of Chemistry, University of Bari (Italy); MIP-CNR sec Bari (Italy)

    2007-12-15

    The classification of meteorites when geological analysis is unfeasible is generally made by the spectral line emission ratio of some characteristic elements. Indeed when a meteorite impacts Earth's atmosphere, hot plasma is generated, as a consequence of the braking effect of air, with the consequent ablation of the falling body. Usually, by the plasma emission spectrum, the meteorite composition is determined, assuming the Boltzmann equilibrium. The plasma generated during Laser Induced Breakdown Spectroscopy (LIBS) experiment shows similar characteristics and allows one to verify the mentioned method with higher accuracy. On the other hand the study of Laser Induced Breakdown Spectroscopy on meteorite can be useful for both improving meteorite classification methods and developing on-flight techniques for asteroid investigation. In this paper certified meteorites belonging to different typologies have been investigated by LIBS: Dofhar 461 (lunar meteorite), Chondrite L6 (stony meteorite), Dofhar 019 (Mars meteorite) and Sikhote Alin (irony meteorite)

  20. Fluorescence correlation spectroscopy in laser gradient field

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Fluorescence correlation spectroscopy (FCS) is capable of probing dynamic processes in living biological systems. From photon fluctuation of fluorescing particles which diffuse through a small detection volume, FCS reveals information on the concentration and the structure of the particles, as well as information on microscopic environment.In this note, we study the radiation forces experienced by Rayleigh particles in a laser field in details, and analyze the effects of gradient field on FCS measurements.

  1. Elemental Analysis of Soils by Laser Induced Breakdown Spectroscopy

    Science.gov (United States)

    Gondal, Mohammed Ashraf; Dastageer, Mohamed A.

    The chemical and elemental composition of soil is very complex as it contains many constituents like minerals, organic matters, living organisms, fossils, air and water. Considering the diversity of soil contents, quality and usability, a systematic scientific study on the elemental and chemical composition of soil is very important. In order to study the chemical composition of soil, Laser induced breakdown spectroscopy (LIBS) has been applied recently. The important features of LIBS system and its applications for the measurement of nutrients in green house soil, on-line monitoring of remediation process of chromium polluted soil, determination of trace elements in volcanic erupted soil samples collected from ancient cenozoic lava eruption sites and detection of toxic metals in Gulf war oil spill contaminated soil using LIBS are described in this chapter.

  2. Development of on-line FTIR spectroscopy for siloxane detection in biogas to enhance carbon contactor management.

    Science.gov (United States)

    Hepburn, C A; Vale, P; Brown, A S; Simms, N J; McAdam, E J

    2015-08-15

    Activated carbon filters are used to limit engine damage by siloxanes when biogas is utilised to provide electricity. However, carbon filter siloxane removal performance is poorly understood as until recently, it had not been possible to measure siloxanes on-line. In this study, on-line Fourier Transform Infrared (FTIR) spectroscopy was developed to measure siloxane concentration in real biogas both upstream (86.1-157.5mg m(-3)) and downstream (2.2-4.3mg m(-3)) of activated carbon filters. The FTIR provided reasonable precision upstream of the carbon vessel with a root mean square error of 10% using partial least squares analysis. However, positive interference from volatile organic carbons was observed in downstream gas measurements limiting precision at the outlet to an RMSE of 1.5mg m(-3) (47.8%). Importantly, a limit of detection of 3.2mg m(-3) was identified which is below the recommended siloxane limit and evidences the applicability of on-line FTIR for this application.

  3. Applications of absorption spectroscopy using quantum cascade lasers.

    Science.gov (United States)

    Zhang, Lizhu; Tian, Guang; Li, Jingsong; Yu, Benli

    2014-01-01

    Infrared laser absorption spectroscopy (LAS) is a promising modern technique for sensing trace gases with high sensitivity, selectivity, and high time resolution. Mid-infrared quantum cascade lasers, operating in a pulsed or continuous wave mode, have potential as spectroscopic sources because of their narrow linewidths, single mode operation, tunability, high output power, reliability, low power consumption, and compactness. This paper reviews some important developments in modern laser absorption spectroscopy based on the use of quantum cascade laser (QCL) sources. Among the various laser spectroscopic methods, this review is focused on selected absorption spectroscopy applications of QCLs, with particular emphasis on molecular spectroscopy, industrial process control, combustion diagnostics, and medical breath analysis.

  4. Laser techniques for spectroscopy of core-excited atomic levels

    Science.gov (United States)

    Harris, S. E.; Young, J. F.; Falcone, R. W.; Rothenberg, J. E.; Willison, J. R.

    1982-01-01

    We discuss three techniques which allow the use of tunable lasers for high resolution and picosecond time scale spectroscopy of core-excited atomic levels. These are: anti-Stokes absorption spectroscopy, laser induced emission from metastable levels, and laser designation of selected core-excited levels.

  5. Ultrafast laser spectroscopy in complex solid state materials

    Energy Technology Data Exchange (ETDEWEB)

    Li, Tianqi [Iowa State Univ., Ames, IA (United States)

    2014-12-01

    This thesis summarizes my work on applying the ultrafast laser spectroscopy to the complex solid state materials. It shows that the ultrafast laser pulse can coherently control the material properties in the femtosecond time scale. And the ultrafast laser spectroscopy can be employed as a dynamical method for revealing the fundamental physical problems in the complex material systems.

  6. Time resolved laser-induced breakdown spectroscopy for calcium concentration detection in water

    Institute of Scientific and Technical Information of China (English)

    WU Jiang-lai; LU Yuan; Li Ying; CHENG Kai; GUO Jin-jia; ZHENG Rong-er

    2011-01-01

    @@ The laser induced breakdown spectroscopy (LIBS) is an element analysis technique with the advantages of real time detection, simultaneous multi-element identification, and in-situ and stand-off capacities.To evaluate its potential of ocean applications, in this paper, the time resolved laser-induced breakdown spectroscopy for calcium concentration detection in water is investigated.With the optimum experimental parameters, the plasma emission lifetime is determined to be about 500 ns with 532 nm laser excitation, and 1000 ns with 1064 nm laser excitation.The lowest detection concentration of 50ppm is achieved for calcium detection in CaC12 water solution using the 532 nm LIBS.Even better detection sensitivity is achieved using the 1064 nm LIBS, and the resulted lowest detection concentration of calcium is 25 ppm.The results suggest that it is feasible to develop LIBS as an on-line sensor for metal element monitoring in the sea.

  7. Study on on-line processing of the chaos laser radar using FPGA

    OpenAIRE

    2005-01-01

    Today, a car industry puts effort into making intelligent car to realize a safe and comfortable car society. As one of the sensing technology, laser radar is widely studied as in-car radar. The received signal in the laser radar becomes to be buried in noise with increasing distance. When the long distance is measured, it needs a high power laser, or the repetitive process that uses multiplication and integration. Therefore, a new type of the chaos laser radar has been studied. This laser rad...

  8. Laser spectroscopy used in nuclear physics; La spectroscopie laser appliquee a la physique nucleaire

    Energy Technology Data Exchange (ETDEWEB)

    Le Blanc, F

    2001-04-05

    The study of nuclear shapes is a basic topic since it constitutes an excellent ground for testing and validating nuclear models. Measurements of the electron quadrupolar moment, of the nuclear charge radius and of the magnetic dipolar moment shed light on the nuclear deformation. Laser spectroscopy is a specific tool for such measurements, it is based on the interaction of the nucleus with the surrounding electron cloud (hyperfine structure), it is then an external approach of the shape of the nucleus whereas the classical nuclear spectroscopy ({alpha}, {beta} or {gamma}) gives information on the deformation from the inside of the nucleus. The author describes 2 techniques of laser spectroscopy: the colinear spectroscopy directly applied to a beam issued from an isotope separator and the resonant ionization spectroscopy linked with atom desorption that allows the study of particular nuclei. In order to illustrate both methods some effective measurements are presented: - the colinear spectroscopy has allowed the achievement of the complete description of the isomeric state (T = 31 years) of hafnium-178; - The experiment Complis has revealed an unexpected even-odd zigzag effect on very neutron-deficient platinum isotopes; and - the comparison of 2 isotopes of gold and platinum with their isomers has shown that the inversion of 2 levels of neutron, that was found out by nuclear spectroscopy, is in fact a consequence of a change in the nuclear shape. (A.C.)

  9. Laser photoluminescence spectroscopy of photodissociation fragments

    Science.gov (United States)

    Jackson, W. M.; Cody, R. J.

    1974-01-01

    Laser induced photoluminescence spectroscopy has been used to study the energy partitioning among CN fragments produced by the photodissociation of C2N2. The CN radicals are produced in both the A 2Pi and the X 2Sigma+ states. The A state is formed primarily in the nu-prime = 0 level, and the X state is formed in the lower vibrational levels. Since the photodissociation process does not produce the maximum amount of vibrational excitation in the CN fragments, it is suggested that the excess energy goes into either translational and/or rotational excitation of the CN.

  10. A novel differential velocity modulation laser spectroscopy

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Experimental investigation of a novel differential velocity modulation laser spectroscopy is reported and demonstrated with the spectra of Meinel system. The S/N ratio excesses 500︰1, about 60 times higher than that with the traditional non-differential technique. With this technique, we obtained the high-resolution electronic absorption spectra of (1, 0) vibration-al band of CS+ for the first time. It is confirmed that this technique will be a powerful method and receive wide application in studies of new molecular ions.

  11. On-line experimental results of an argon gas cell-based laser ion source (KEK Isotope Separation System)

    Science.gov (United States)

    Hirayama, Y.; Watanabe, Y. X.; Imai, N.; Ishiyama, H.; Jeong, S. C.; Jung, H. S.; Miyatake, H.; Oyaizu, M.; Kimura, S.; Mukai, M.; Kim, Y. H.; Sonoda, T.; Wada, M.; Huyse, M.; Kudryavtsev, Yu.; Van Duppen, P.

    2016-06-01

    KEK Isotope Separation System (KISS) has been developed at RIKEN to produce neutron rich isotopes with N = 126 to study the β -decay properties for application to astrophysics. The KISS is an element-selective mass-separation system which consists of an argon gas cell-based on laser ion source for atomic number selection and an ISOL mass-separation system. The argon gas cell of KISS is a key component to stop and collect the unstable nuclei produced in a multi-nucleon transfer reaction, where the isotopes of interest will be selectively ionized using laser resonance ionization. We have performed off- and on-line experiments to study the basic properties of the gas cell as well as of the KISS. We successfully extracted the laser-ionized stable 56Fe (direct implantation of a 56Fe beam into the gas cell) atoms and 198Pt (emitted from the 198Pt target by elastic scattering with a 136Xe beam) atoms from the KISS during the commissioning on-line experiments. We furthermore extracted laser-ionized unstable 199Pt atoms and confirmed that the measured half-life was in good agreement with the reported value.

  12. Laser fabrication and spectroscopy of organic nanoparticles.

    Science.gov (United States)

    Asahi, T; Sugiyama, T; Masuhara, H

    2008-12-01

    In working with nanoparticles, researchers still face two fundamental challenges: how to fabricate the nanoparticles with controlled size and shape and how to characterize them. In this Account, we describe recent advances in laser technology both for the synthesis of organic nanoparticles and for their analysis by single nanoparticle spectroscopy. Laser ablation of organic microcrystalline powders in a poor solvent has opened new horizons for the synthesis of nanoparticles because the powder sample is converted directly into a stable colloidal solution without additives and chemicals. By tuning laser wavelength, pulse width, laser fluence, and total shot number, we could control the size and phase of the nanoparticles. For example, we describe nanoparticle formation of quinacridone, a well-known red pigment, in water. By modifying the length of time that the sample is excited by the laser, we could control the particle size (30-120 nm) for nanosecond excitation down to 13 nm for femtosecond irradiation. We prepared beta- and gamma-phase nanoparticles from the microcrystal with beta-phase by changing laser wavelength and fluence. We present further results from nanoparticles produced from several dyes, C(60), and an anticancer drug. All the prepared colloidal solutions were transparent and highly dispersive. Such materials could be used for nanoscale device development and for biomedical and environmental applications. We also demonstrated the utility of single nanoparticle spectroscopic analysis in the characterization of organic nanoparticles. The optical properties of these organic nanoparticles depend on their size within the range from a few tens to a few hundred nanometers. We observed perylene nanoscrystals using single-particle spectroscopy coupled with atomic force microscopy. Based on these experiments, we proposed empirical equations explaining their size-dependent fluorescence spectra. We attribute the size effect to the change in elastic properties of

  13. On-line implementation and first operation of the Laser Ion Source and Trap at ISOLDE/CERN

    Energy Technology Data Exchange (ETDEWEB)

    Fink, D.A., E-mail: daniel.fink@cern.ch [CERN, 1211 Geneva 23 (Switzerland); Max-Planck-Institut für Kernphysik, 69117 Heidelberg (Germany); Fakultät für Physik und Astronomie, Ruprecht-Karls-Universität, 69120 Heidelberg (Germany); Richter, S.D. [Institut für Physik, Johannes Gutenberg-Universität, 55099 Mainz (Germany); Blaum, K. [Max-Planck-Institut für Kernphysik, 69117 Heidelberg (Germany); Catherall, R.; Crepieux, B.; Fedosseev, V.N. [CERN, 1211 Geneva 23 (Switzerland); Gottberg, A. [CERN, 1211 Geneva 23 (Switzerland); Instituto de Estructura de la Materia, CSIC, 28006 Madrid (Spain); Kron, T. [Institut für Physik, Johannes Gutenberg-Universität, 55099 Mainz (Germany); Marsh, B.A. [CERN, 1211 Geneva 23 (Switzerland); Mattolat, C.; Raeder, S. [Institut für Physik, Johannes Gutenberg-Universität, 55099 Mainz (Germany); Rossel, R.E. [CERN, 1211 Geneva 23 (Switzerland); Institut für Physik, Johannes Gutenberg-Universität, 55099 Mainz (Germany); Faculty of Design, Computer Science and Media, Hochschule RheinMain, 65197 Wiesbaden (Germany); Rothe, S. [CERN, 1211 Geneva 23 (Switzerland); Institut für Physik, Johannes Gutenberg-Universität, 55099 Mainz (Germany); Schwellnus, F. [Institut für Physik, Johannes Gutenberg-Universität, 55099 Mainz (Germany); and others

    2015-02-01

    Highlights: • The Laser Ion Source and Trap (LIST) was successfully operated on-line at ISOLDE. • LIST showed no signs of degradation after 48 h of intense proton irradiation. • Transmission, selectivity, efficiency, time structure were extensively characterized. • Suppression factor for surface-ionized isobaric contaminants is more than 10{sup 3}–10{sup 4}. • Loss in LIST efficiency compared to RILIS operation is only a factor of 20. - Abstract: At radioactive ion beam facilities like ISOLDE at CERN, a high purity of the element of interest in the ion beam is essential for most experiments on exotic nuclei. Due to its unique combination of high ionization efficiency and ultimate elemental selectivity, the Resonance Ionization Laser Ion Source, RILIS, has become the most frequently used ion source at ISOLDE and at the majority of similar facilities worldwide. However, isobaric contamination predominantly stemming from unspecific surface ionization may still introduce severe limitations. By applying the highly selective resonance ionization technique inside a radio-frequency quadrupole ion guide structure, the novel approach of the Laser Ion Source and Trap, LIST, suppresses surface ionized isobaric contaminants by an electrostatic repelling potential. Following extensive feasibility studies and off-line tests, the LIST device has been adapted and refined to match the stringent operational constraints and to survive the hostile environment of the ISOLDE front-end region enclosing the highly radioactive nuclear reaction target. The LIST operation was successfully demonstrated for the first time on-line at ISOLDE during two experiments, attesting its suitability for radioactive isotope production under routine conditions. Data of these on-line characterization measurements confirm a suppression of surface-ionized isobars by more than a factor of 1000 in accordance to off-line studies that were carried out for the preparation of the on-line experiments

  14. A new lithium-ion battery internal temperature on-line estimate method based on electrochemical impedance spectroscopy measurement

    Science.gov (United States)

    Zhu, J. G.; Sun, Z. C.; Wei, X. Z.; Dai, H. F.

    2015-01-01

    The power battery thermal management problem in EV (electric vehicle) and HEV (hybrid electric vehicle) has been widely discussed, and EIS (electrochemical impedance spectroscopy) is an effective experimental method to test and estimate the status of the battery. Firstly, an electrochemical-based impedance matrix analysis for lithium-ion battery is developed to describe the impedance response of electrochemical impedance spectroscopy. Then a method, based on electrochemical impedance spectroscopy measurement, has been proposed to estimate the internal temperature of power lithium-ion battery by analyzing the phase shift and magnitude of impedance at different ambient temperatures. Respectively, the SoC (state of charge) and temperature have different effects on the impedance characteristics of battery at various frequency ranges in the electrochemical impedance spectroscopy experimental study. Also the impedance spectrum affected by SoH (state of health) is discussed in the paper preliminary. Therefore, the excitation frequency selected to estimate the inner temperature is in the frequency range which is significantly influenced by temperature without the SoC and SoH. The intrinsic relationship between the phase shift and temperature is established under the chosen excitation frequency. And the magnitude of impedance related to temperature is studied in the paper. In practical applications, through obtaining the phase shift and magnitude of impedance, the inner temperature estimation could be achieved. Then the verification experiments are conduced to validate the estimate method. Finally, an estimate strategy and an on-line estimation system implementation scheme utilizing battery management system are presented to describe the engineering value.

  15. Tomographic laser absorption spectroscopy using Tikhonov regularization.

    Science.gov (United States)

    Guha, Avishek; Schoegl, Ingmar

    2014-12-01

    The application of tunable diode laser absorption spectroscopy (TDLAS) to flames with nonhomogeneous temperature and concentration fields is an area where only few studies exist. Experimental work explores the performance of tomographic reconstructions of species concentration and temperature profiles from wavelength-modulated TDLAS measurements within the plume of an axisymmetric McKenna burner. Water vapor transitions at 1391.67 and 1442.67 nm are probed using calibration-free wavelength modulation spectroscopy with second harmonic detection (WMS-2f). A single collimated laser beam is swept parallel to the burner surface, where scans yield pairs of line-of-sight (LOS) data at multiple radial locations. Radial profiles of absorption data are reconstructed using Tikhonov regularized Abel inversion, which suppresses the amplification of experimental noise that is typically observed for reconstructions with high spatial resolution. Based on spectral data reconstructions, temperatures and mole fractions are calculated point-by-point. Here, a least-squares approach addresses difficulties due to modulation depths that cannot be universally optimized due to a nonuniform domain. Experimental results show successful reconstructions of temperature and mole fraction profiles based on two-transition, nonoptimally modulated WMS-2f and Tikhonov regularized Abel inversion, and thus validate the technique as a viable diagnostic tool for flame measurements.

  16. On-line near infrared spectroscopy as a Process Analytical Technology (PAT) tool to control an industrial seeded API crystallization.

    Science.gov (United States)

    Schaefer, C; Lecomte, C; Clicq, D; Merschaert, A; Norrant, E; Fotiadu, F

    2013-09-01

    The final step of an active pharmaceutical ingredient (API) manufacturing synthesis process consists of a crystallization during which the API and residual solvent contents have to be quantified precisely in order to reach a predefined seeding point. A feasibility study was conducted to demonstrate the suitability of on-line NIR spectroscopy to control this step in line with new version of the European Medicines Agency (EMA) guideline [1]. A quantitative method was developed at laboratory scale using statistical design of experiments (DOE) and multivariate data analysis such as principal component analysis (PCA) and partial least squares (PLS) regression. NIR models were built to quantify the API in the range of 9-12% (w/w) and to quantify the residual methanol in the range of 0-3% (w/w). To improve the predictive ability of the models, the development procedure encompassed: outliers elimination, optimum model rank definition, spectral range and spectral pre-treatment selection. Conventional criteria such as, number of PLS factors, R(2), root mean square errors of calibration, cross-validation and prediction (RMSEC, RMSECV, RMSEP) enabled the selection of three model candidates. These models were tested in the industrial pilot plant during three technical campaigns. Results of the most suitable models were evaluated against to the chromatographic reference methods. Maximum relative bias of 2.88% was obtained about API target content. Absolute bias of 0.01 and 0.02% (w/w) respectively were achieved at methanol content levels of 0.10 and 0.13% (w/w). The repeatability was assessed as sufficient for the on-line monitoring of the 2 analytes. The present feasibility study confirmed the possibility to use on-line NIR spectroscopy as a PAT tool to monitor in real-time both the API and the residual methanol contents, in order to control the seeding of an API crystallization at industrial scale. Furthermore, the successful scale-up of the method proved its capability to be

  17. Laser frequency combs for precision astronomical spectroscopy

    Science.gov (United States)

    Ycas, Gabriel George

    Laser frequency comb sources promise to enable precision astronomical spectroscopy at the 10-11 level, enabling observations aimed at locating potentially habitable planets. Frequency combs allow for the simultaneous generation of thousands of individual laser lines, each with optical frequency referenced to the SI second, and are capable of providing a bright, simple, and stable spectrum ideal for the calibration of grating-based astronomical spectrographs. In order for frequency combs and spectrographs to be used in tandem, key technical challenges must be addressed. Most critically, it is necessary to increase the mode-spacing of the frequency comb to more than 20 GHz while simultaneously retaining the stability and broad optical bandwidth of the comb. This thesis also offers an overview of modern astronomical spectroscopy, along with a thorough discussion of the technical details of mode-locked lasers and frequency comb design. This thesis begins by presenting a frequency comb system with mode-spacing of 25 GHz suitable for the near-infrared between 1500 and 1700 nm. Examples are shown from the successful calibration of the Penn State University Pathfinder astronomical spectrograph located at the Hobby-Eberly telescope using the frequency comb system. In the second half of the thesis, the erbium-fiber frequency comb is shown to generate highly coherent, ultrafast, and bright pulses at 1050 nm. The short duration and high peak power of these pulses enable coherent and continuous extension of the comb to visible wavelengths. Next, an accurate model of a nonlinear fiber optic amplifiers is developed and tested, then applied to optimize the selection of fiber lengths in the design of ultrafast nonlinear fiber-optic systems. Finally, a broad-bandwidth optical filter cavity for the generation of a 980--1110 nm suitable for calibration of next-generation spectrographs was designed and tested.

  18. Laser Spectroscopy of Antiprotonic Helium Atoms

    CERN Multimedia

    2002-01-01

    %PS205 %title\\\\ \\\\Following the discovery of metastable antiprotonic helium atoms ($\\overline{p}He^{+} $) at KEK in 1991, systematic studies of their properties were made at LEAR from 1991 to 1996. In the first two years the lifetime of $\\overline{p}He^{+}$ in liquid and gaseous helium at various temperatures and pressures was measured and the effect of foreign gases on the lifetime of these atoms was investigated. Effects were also discovered which gave the antiproton a 14\\% longer lifetime in $^4$He than in $^3$He, and resulted in important differences in the shape of the annihilation time spectra in the two isotopes.\\\\ \\\\Since 1993 laser spectroscopy of the metastable $\\overline{p}He^{+}$ atoms became the main focus of PS205. Transitions were stimulated between metastable and non-metastable states of the $\\overline{p}He^{+}$ atom by firing a pulsed dye laser beam into the helium target every time an identified metastable atom was present (Figure 1). If the laser frequency matched the transition energy, the...

  19. Laser Spectroscopy of bi-alkali molecules

    Science.gov (United States)

    Dutta, Sourav; Altaf, A.; Lorenz, J.; Elliott, D.; Chen, Yong

    2010-03-01

    We report a study of laser spectroscopy of bi-alkali molecules, such as Li2, Rb2 and LiRb (work is in progress). We have constructed a dual-species (Li/Rb) heat pipe oven with a side viewport. The molecular fluorescence is excited by a dye laser with Rh6G dye (operating between 564 nm and 610 nm) and various home-made diode lasers (operating near 635 nm and 665 nm). The fluorescence is recorded using a .5ex1 -.1em/ -.15em.25ex4 m monochromator with a 0.1 nm (˜ 3 cm-1) spectral resolution. Transitions to the X^1σg^+ in Li2 and Rb2 have been measured and studies on LiRb are in progress. Molecular parameters, such as force constant, may be obtained from the analysis of the data (which agree with previously known values to within ˜ 3%). Using the known values of dissociation energy De and harmonic frequency φe for the alkali dimers, we also demonstrate that simple calculations with Morse potential approximation can be used to estimate the molecular transition wavelengths to within a few (1-3) nanometers from the experimentally measured values. Such information will aid in creating cold molecules via photoassociation in a dual species magneto-optical trap (LiRb in our case).

  20. [Influence of laser power and incident angle as well as testing distance on laser inducted breakdown spectroscopy (LIBS) technology for spectroscopy diagnosis and multi-element analysis].

    Science.gov (United States)

    Zhai, Yang; Zhu, Ri-Hong; Shen, Hua; Gu, Jin-Liang

    2011-10-01

    Laser inducted breakdown spectroscopy (LIBS) technology has been used widely for the multi-element analysis of different samples and also an effective way to realize the spectroscopy diagnosis applied to calculating the electron temperature and vibration-rotation temperature etc of some certain elements. It is a highly effective measurement for its non-contact and nondestructive on-line analysis with the help of a high-speed response CCD camera. In the present paper, the authors tested an alley though LIBS technology to determine its elements in terms of species and quantities and also discussed some influences of the incident angle and the power changes of the laser beam as well as the measurement distance changes on the experimental results and and gave appropriate theoretical explanation.

  1. Achieving sensitive, high-resolution laser spectroscopy at CRIS

    Energy Technology Data Exchange (ETDEWEB)

    Groote, R. P. de [Instituut voor Kern- en Stralingsfysica, KU Leuven (Belgium); Lynch, K. M., E-mail: kara.marie.lynch@cern.ch [EP Department, CERN, ISOLDE (Switzerland); Wilkins, S. G. [The University of Manchester, School of Physics and Astronomy (United Kingdom); Collaboration: the CRIS collaboration

    2017-11-15

    The Collinear Resonance Ionization Spectroscopy (CRIS) experiment, located at the ISOLDE facility, has recently performed high-resolution laser spectroscopy, with linewidths down to 20 MHz. In this article, we present the modifications to the beam line and the newly-installed laser systems that have made sensitive, high-resolution measurements possible. Highlights of recent experimental campaigns are presented.

  2. Laboratory diode laser spectroscopy in molecular planetary astronomy

    Science.gov (United States)

    Jennings, D. E.

    1988-01-01

    Infrared spectroscopy of planetary atmospheres is performed at high spectral resolution comparable to that in the laboratory. This requires that laboratory spectroscopy use the highest resolution and the most accurate techniques. Tunable diode laser spectroscopy can supply many of the spectroscopic parameters needed by astronomers. In particular, line positions, line strengths, and collisional line widths are measured with diode lasers, and these are often among the best values available. Diode laser spectra are complimentary to lower resolution, broader-coverage Fourier transform spectra. Certain procedures must be adopted, however, when using diode lasers, for determining their output characteristics and for calibrating each spectrum against quality references.

  3. Molecular Laser Spectroscopy as a Tool for Gas Analysis Applications

    Directory of Open Access Journals (Sweden)

    Javis Anyangwe Nwaboh

    2011-01-01

    Full Text Available We have used the traceable infrared laser spectrometric amount fraction measurement (TILSAM method to perform absolute concentration measurements of molecular species using three laser spectroscopic techniques. We report results performed by tunable diode laser absorption spectroscopy (TDLAS, quantum cascade laser absorption spectroscopy (QCLAS, and cavity ring down spectroscopy (CRDS, all based on the TILSAM methodology. The measured results of the different spectroscopic techniques are in agreement with respective gravimetric values, showing that the TILSAM method is feasible with all different techniques. We emphasize the data quality objectives given by traceability issues and uncertainty analyses.

  4. High performance liquid chromatography with on-line dual quantum cascade laser detection for the determination of carbohydrates, alcohols and organic acids in wine and grape juice

    Science.gov (United States)

    Kuligowski, J.; Quintás, G.; Lendl, B.

    2010-06-01

    In the present study the simultaneous use of two quantum cascade lasers (QC-lasers) was investigated for the on-line detection in high performance liquid chromatography (HPLC). An optical set-up based on three gold mirrors and a ZnSe beam splitter was used to direct the emitted laser light trough a liquid flow cell with an optical path length of 52 μm onto a mercury-cadmium-telluride (MCT) detector. Using the separation of eight components of wine and grape juice as an example, on-line dual QC-laser detection in HPLC could be shown successfully for the first time.

  5. Ultrafast Laser-Based Spectroscopy and Sensing: Applications in LIBS, CARS, and THz Spectroscopy

    Directory of Open Access Journals (Sweden)

    Megan R. Leahy-Hoppa

    2010-04-01

    Full Text Available Ultrafast pulsed lasers find application in a range of spectroscopy and sensing techniques including laser induced breakdown spectroscopy (LIBS, coherent Raman spectroscopy, and terahertz (THz spectroscopy. Whether based on absorption or emission processes, the characteristics of these techniques are heavily influenced by the use of ultrafast pulses in the signal generation process. Depending on the energy of the pulses used, the essential laser interaction process can primarily involve lattice vibrations, molecular rotations, or a combination of excited states produced by laser heating. While some of these techniques are currently confined to sensing at close ranges, others can be implemented for remote spectroscopic sensing owing principally to the laser pulse duration. We present a review of ultrafast laser-based spectroscopy techniques and discuss the use of these techniques to current and potential chemical and environmental sensing applications.

  6. Rapid on-line detection and grading of wooden breast myopathy in chicken fillets by near-infrared spectroscopy

    Science.gov (United States)

    Veiseth-Kent, Eva; Høst, Vibeke; Løvland, Atle

    2017-01-01

    The main objective of this work was to develop a method for rapid and non-destructive detection and grading of wooden breast (WB) syndrome in chicken breast fillets. Near-infrared (NIR) spectroscopy was chosen as detection method, and an industrial NIR scanner was applied and tested for large scale on-line detection of the syndrome. Two approaches were evaluated for discrimination of WB fillets: 1) Linear discriminant analysis based on NIR spectra only, and 2) a regression model for protein was made based on NIR spectra and the estimated concentrations of protein were used for discrimination. A sample set of 197 fillets was used for training and calibration. A test set was recorded under industrial conditions and contained spectra from 79 fillets. The classification methods obtained 99.5–100% correct classification of the calibration set and 100% correct classification of the test set. The NIR scanner was then installed in a commercial chicken processing plant and could detect incidence rates of WB in large batches of fillets. Examples of incidence are shown for three broiler flocks where a high number of fillets (9063, 6330 and 10483) were effectively measured. Prevalence of WB of 0.1%, 6.6% and 8.5% were estimated for these flocks based on the complete sample volumes. Such an on-line system can be used to alleviate the challenges WB represents to the poultry meat industry. It enables automatic quality sorting of chicken fillets to different product categories. Manual laborious grading can be avoided. Incidences of WB from different farms and flocks can be tracked and information can be used to understand and point out main causes for WB in the chicken production. This knowledge can be used to improve the production procedures and reduce today’s extensive occurrence of WB. PMID:28278170

  7. Comparison of simultaneous on-line optical and acoustic laser damage detection methods in the nanosecond pulse duration domain

    Science.gov (United States)

    Somoskoi, T.; Vass, Cs; Mero, M.; Mingesz, R.; Bozoki, Z.; Osvay, K.

    2015-05-01

    We carried out single-shot laser-induced damage threshold measurements on dielectric high reflectors guided by the corresponding ISO standard. Four simultaneous on-line detection techniques were tested and compared using 532 nm, 9 ns and 266 nm, 6 ns laser pulses. Two methods, microscope aided visual inspection and detection of scattered light off the damaged surface, were based on optical signals. The other two techniques exploited the acoustic waves accompanying a damage event in ambient air and in the substrate by a microphone and a piezoelectric sensor, respectively. A unified criterion based on the statistical analysis of the detector signals was applied to assign an objective and unambiguous damage threshold value for all of our diverse detection methods. Microscope aided visual inspection showed the lowest damage thresholds for both wavelengths. However, the sensitivity of the other three techniques proved to be only slightly lower.

  8. Laser spectroscopy of neutron deficient Sn isotopes

    CERN Multimedia

    We propose to study the ground state properties of neutron-deficient Sn isotopes towards the doubly-magic nucleus $^{100}$Sn. Nuclear spins, changes in the rms charge radii and electromagnetic moments of $^{101-121}$Sn will be measured by laser spectroscopy using the CRIS experimental beam line. These ground-state properties will help to clarify the evolution of nuclear structure properties approaching the $\\textit{N = Z =}$ 50 shell closures. The Sn isotopic chain is currently the frontier for the application of state-of-the-art ab-initio calculations. Our knowledge of the nuclear structure of the Sn isotopes will set a benchmark for the advances of many-body methods, and will provide an important test for modern descriptions of the nuclear force.

  9. Laser-Induced Breakdown Spectroscopy: Capabilities and Applications

    Science.gov (United States)

    2010-07-01

    sample preparation. 14 6. References 1. Cremers D.A.; Radziemski, L. J. Handbook of Laser-Induced Breakdown Spectroscopy; West Sussex, England...30 (21), 2882–2884. 17. Salle, B.; Lacour, J. L.; Vors, E.; Fichet, P.; Maurice, S.; Cremers , D. A.; et al. Laser- Induced Breakdown Spectroscopy...90. Martin , M. Z.; Labbe, N.; Andre, N.; Harris, R.; Ebinger, M.; Wullschleger, S. D.; et al. High Resolution Applications of Laser-Induced

  10. Vibrational Spectroscopy of Laser Cooled CaH

    Science.gov (United States)

    2015-10-28

    Molecular ions trapped in RF Paul traps and sympathetically- cooled with laser - cooled atomic ions have been shown to be a great platform to measure...Approved for public release; distribution is unlimited. Vibrational Spectroscopy of Laser Cooled CaH+ The views, opinions and/or findings contained in...Angeles, CA 90095 -1406 ABSTRACT Vibrational Spectroscopy of Laser Cooled CaH+ Report Title Cold molecules and molecular ions are leading to a renaissance

  11. Fiber-distributed multi-channel open-path H2S sensor based on tunable diode laser absorption spectroscopy

    Institute of Scientific and Technical Information of China (English)

    Dong Chen; Wenqing Liu; Yujun Zhang; Jianguo Liu; Ruifeng Kan; Min Wang; Xi Fang; Yiben Cui

    2007-01-01

    Tunable diode laser based gas detectors are now being used in a wide variety of applications for safety and environmental interest. A fiber-distributed multi-channel open-path H2S sensor based on tunable diode laser absorption spectroscopy (TDLAS) is developed, the laser used is a telecommunication near infrared distributed feed-back (DFB) tunable diode laser, combining with wavelength modulation specby combining optical fiber technique. An on-board reference cell provides on-line sensor calibration and almost maintenance-free operation. The sensor is suitable for large area field H2S monitoring application.

  12. On-line monitoring of nitrogenase activity in cyanobacteria by sensitive laser photoacoustic detection of ethylene

    NARCIS (Netherlands)

    Zuckermann, H.; Staal, M.J.; Stal, L.J.; Reuss, J.; te Lintel Hekkert, S.; Harren, F.J.M.; Parker, D.H.

    1997-01-01

    A new and extremely sensitive method for measuring nitrogenase activity through acetylene reduction is presented. Ethylene produced by nitrogenase-mediated reduction of acetylene is detected by using laser photoacoustics (LPA). This method possesses a detection limit making it 3 orders of magnitude

  13. Laser tweezers Raman spectroscopy of single cells

    Science.gov (United States)

    Chen, De

    Raman scattering is an inelastic collision between the vibrating molecules inside the sample and the incident photons. During this process, energy exchange takes place between the photon and the scattering molecule. By measuring the energy change of the photon, the molecular vibration mode can be probed. The vibrational spectrum contains valuable information about the disposition of atomic nuclei and chemical bonds within a molecule, the chemical compositions and the interactions between the molecule and its surroundings. In this dissertation, laser tweezers Raman spectroscopy (LTRS) technique is applied for the analysis of biological cells and human cells at single cell level. In LTRS, an individual cell is trapped in aqueous medium with laser tweezers, and Raman scattering spectra from the trapped cell are recorded in real-time. The Raman spectra of these cells can be used to reveal the dynamical processes of cell growth, cell response to environment changes, and can be used as the finger print for the identification of a bacterial cell species. Several biophysical experiments were carried out using LTRS: (1) the dynamic germination process of individual spores of Bacillus thuringiensis was detected via Ca-DPA, a spore-specific biomarker molecule; (2) inactivation and killing of Bacillus subtilis spores by microwave irradiation and wet heat were studied at single cell level; (3) the heat shock activation process of single B. subtilis spores were analyzed, in which the reversible transition from glass-like state at low temperature to liquid-like state at high temperature in spore was revealed at the molecular level; (4) the kinetic processes of bacterial cell lysis of E. coli by lysozyme and by temperature induction of lambda phage were detected real-time; (5) the fixation and rehydration of human platelets were quantitatively evaluated and characterized with Raman spectroscopy method, which provided a rapid way to quantify the quality of freeze-dried therapeutic

  14. COMPLIS: COllinear spectroscopy Measurements using a Pulsed Laser Ion Source

    CERN Multimedia

    2002-01-01

    A Pulsed Laser spectroscopy experiment has been installed for the study of hyperfine structure and isotope shift of refractory and daughter elements from ISOLDE beams. It includes decelerated ion-implantation, element-selective laser ionization, magnetic and time-of-flight mass separation. The laser spectroscopy has been performed on the desorbed atoms in a set-up at ISOLDE-3 but later on high resolution laser collinear spectroscopy with the secondary pulsed ion beam is planned for the Booster ISOLDE set-up. During the first operation time of ISOLDE-3 we restricted our experiments to Doppler-limited resonant ionization laser and $\\gamma$-$\\gamma$ nuclear spectroscopy on neutron deficient platinum isotopes of even mass number down to A~=~186 and A~=~179 respectively. These isotopes have been produced by implantation of radioactive Hg and their subsequent $\\beta$-decay.

  15. Comprehensive two-dimensional liquid chromatography with on-line Fourier-transform-infrared-spectroscopy detection for the characterization of copolymers

    NARCIS (Netherlands)

    Kok, S.J.; Hankemeier, T.; Schoenmakers, P.J.

    2005-01-01

    The on-line coupling of comprehensive two-dimensional liquid chromatography (liquid chromatography × size-exclusion chromatography, LC × SEC) and infrared (IR) spectroscopy has been realized by means of an IR flow cell. The system has been assessed by the functional-group analysis of a series of

  16. Comprehensive two-dimensional liquid chromatography with on-line Fourier-transform-infrared-spectroscopy detection for the characterization of copolymers

    NARCIS (Netherlands)

    Kok, S.J.; Hankemeier, T.; Schoenmakers, P.J.

    2005-01-01

    The on-line coupling of comprehensive two-dimensional liquid chromatography (liquid chromatography × size-exclusion chromatography, LC × SEC) and infrared (IR) spectroscopy has been realized by means of an IR flow cell. The system has been assessed by the functional-group analysis of a series of sty

  17. Nuclear moments and differences in mean square charge radii of short-lived neon isotopes by collinear laser spectroscopy

    CERN Document Server

    Geithner, R W

    2002-01-01

    The nuclear moments and charge radii of short-lived neon isotopes were measured by the use of collinear laser spectroscopy at the on-line mass separator ISOLDE at CERN. After a general introduction the semiclassical theory of atomic spectra is given and the relevant properties are calculated for neon. The atomic physics section is followed by a description of the experimental setup of the collinear laser spectroscopy experiment at ISOLDE. From the mass separator an isotopically clean ion beam with a kinetic energy of 60 keV is delivered to the experiments. In collinear laser spectroscopy the incoming ion beam from the mass separator is superimposed to a single frequency cw laser beam. The frequency of the atomic transition $\

  18. Emission spectroscopy analysis during Nopal cladodes dethorning by laser ablation

    Science.gov (United States)

    Peña-Díaz, M.; Ponce, L.; Arronte, M.; Flores, T.

    2007-04-01

    Optical emission spectroscopy of the pulsed laser ablation of spines and glochids from Opuntia (Nopal) cladodes was performed. Nopal cladodes were irradiated with Nd:YAG free-running laser pulses on their body, glochids and spines. Emission spectroscopy analyses in the 350-1000 nm region of the laser induced plasma were made. Plasma plume evolution characterization, theoretical calculations of plasma plume temperature and experiments varying the processing atmosphere showed that the process is dominated by a thermally activated combustion reaction which increases the dethorning process efficiency. Therefore, appropriate laser pulse energy for minimal damage of cladodes body and in the area beneath glochids and spines can be obtained.

  19. Emission spectroscopy analysis during Nopal cladodes dethorning by laser ablation

    Energy Technology Data Exchange (ETDEWEB)

    Pena-Diaz, M; Ponce, L; Arronte, M; Flores, T [Laboratorio TecnologIa Laser, CICATA-IPN, Unidad Altamira, Carretera Tampico-Puerto Ind. Altamira, 89600, TAMPS (Mexico)

    2007-04-15

    Optical emission spectroscopy of the pulsed laser ablation of spines and glochids from Opuntia (Nopal) cladodes was performed. Nopal cladodes were irradiated with Nd:YAG free-running laser pulses on their body, glochids and spines. Emission spectroscopy analyses in the 350-1000 nm region of the laser induced plasma were made. Plasma plume evolution characterization, theoretical calculations of plasma plume temperature and experiments varying the processing atmosphere showed that the process is dominated by a thermally activated combustion reaction which increases the dethorning process efficiency. Therefore, appropriate laser pulse energy for minimal damage of cladodes body and in the area beneath glochids and spines can be obtained.

  20. Frequency-comb-referenced tunable diode laser spectroscopy and laser stabilization applied to laser cooling.

    Science.gov (United States)

    Fordell, Thomas; Wallin, Anders E; Lindvall, Thomas; Vainio, Markku; Merimaa, Mikko

    2014-11-01

    Laser cooling of trapped atoms and ions in optical clocks demands stable light sources with precisely known absolute frequencies. Since a frequency comb is a vital part of any optical clock, the comb lines can be used for stabilizing tunable, user-friendly diode lasers. Here, a light source for laser cooling of trapped strontium ions is described. The megahertz-level stability and absolute frequency required are realized by stabilizing a distributed-feedback semiconductor laser to a frequency comb. Simple electronics is used to lock and scan the laser across the comb lines, and comb mode number ambiguities are resolved by using a separate, saturated absorption cell that exhibits easily distinguishable hyperfine absorption lines with known frequencies. Due to the simplicity, speed, and wide tuning range it offers, the employed technique could find wider use in precision spectroscopy.

  1. Collinear laser spectroscopy of atomic cadmium

    CERN Document Server

    Frömmgen, Nadja; Bissell, Mark L; Bieroń, Jacek; Blaum, Klaus; Cheal, Bradley; Flanagan, Kieran; Fritzsche, Stephan; Geppert, Christopher; Hammen, Michael; Kowalska, Magdalena; Kreim, Kim; Krieger, Andreas; Neugart, Rainer; Neyens, Gerda; Rajabali, Mustafa M; Nörtershäuser, Wilfried; Papuga, Jasna; Yordanov, Deyan T

    2015-01-01

    Hyperfine structure $A$ and $B$ factors of the atomic $5s\\,5p\\,\\; ^3\\rm{P}_2 \\rightarrow 5s\\,6s\\,\\; ^3\\rm{S}_1$ transition are determined from collinear laser spectroscopy data of $^{107-123}$Cd and $^{111m-123m}$Cd. Nuclear magnetic moments and electric quadrupole moments are extracted using reference dipole moments and calculated electric field gradients, respectively. The hyperfine structure anomaly for isotopes with $s_{1/2}$ and $d_{5/2}$ nuclear ground states and isomeric $h_{11/2}$ states is evaluated and a linear relationship is observed for all nuclear states except $s_{1/2}$. This corresponds to the Moskowitz-Lombardi rule that was established in the mercury region of the nuclear chart but in the case of cadmium the slope is distinctively smaller than for mercury. In total four atomic and ionic levels were analyzed and all of them exhibit a similar behaviour. The electric field gradient for the atomic $5s\\,5p\\,\\; ^3\\mathrm{P}_2$ level is derived from multi-configuration Dirac-Hartree-Fock calculatio...

  2. Medical Applications of Laser Induced Breakdown Spectroscopy

    Science.gov (United States)

    Pathak, A. K.; Rai, N. K.; Singh, Ankita; Rai, A. K.; Rai, Pradeep K.; Rai, Pramod K.

    2014-11-01

    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.

  3. Cold Antihydrogen for Precise Laser Spectroscopy

    CERN Multimedia

    Gabrielse, G S; Walz, J; Hessels, E A; Tan, J; Oelert, W; George, M C; Grzonka, D J; Kossick, M; Storry, C H; Sefzick, T

    2002-01-01

    %AD-2 %title\\\\ \\\\The Antihydrogen TRAP Collaboration (ATRAP) seeks to do precise laser spectroscopy of antihydrogen. Comparisons of antihydrogen and hydrogen atoms should provide the most stringent test of CPT invariance involving baryons and leptons. ATRAP is an expansion of the TRAP collaboration that developed the techniques to take CERN antiprotons from an energy of 6 MeV (momentum 100 MeV/c) all the way down to thermal equilibrium at 4 K for storage. This storage energy is lower than realized previously by more than ten orders of magnitude. The TRAP techniques include slowing, capturing, electron cooling and stacking of antiprotons. ATRAP and other collaborations will use antiprotons from the Antiproton Decelerator (AD). This new facility makes sense for such experiments because we showed that antiprotons can be accumulated in a trap at much lower expense than was required in the earlier CERN AC-AA-LEAR complex. In the closest approach yet to the production of cold antihydrogen, collaboration members wer...

  4. Quantum cascade laser infrared spectroscopy of single cancer cells

    KAUST Repository

    Patel, Imran

    2017-03-27

    Quantum cascade laser infrared spectroscopy is a next generation novel imaging technique allowing high resolution spectral imaging of cells. We show after spectral pre-processing, identification of different cancer cell populations within minutes.

  5. Compact High Sensitive Laser-Induced Breakdown Spectroscopy Instrument Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Laser induced breakdown spectroscopy (LIBS) is a versatile tool for in situ substance characterization. Existing LIBS instruments are not compact enough for space...

  6. Towards high-resolution laser ionization spectroscopy of the heaviest elements in supersonic gas jet expansion

    Science.gov (United States)

    Ferrer, R.; Barzakh, A.; Bastin, B.; Beerwerth, R.; Block, M.; Creemers, P.; Grawe, H.; de Groote, R.; Delahaye, P.; Fléchard, X.; Franchoo, S.; Fritzsche, S.; Gaffney, L. P.; Ghys, L.; Gins, W.; Granados, C.; Heinke, R.; Hijazi, L.; Huyse, M.; Kron, T.; Kudryavtsev, Yu.; Laatiaoui, M.; Lecesne, N.; Loiselet, M.; Lutton, F.; Moore, I. D.; Martínez, Y.; Mogilevskiy, E.; Naubereit, P.; Piot, J.; Raeder, S.; Rothe, S.; Savajols, H.; Sels, S.; Sonnenschein, V.; Thomas, J-C; Traykov, E.; Van Beveren, C.; Van den Bergh, P.; Van Duppen, P.; Wendt, K.; Zadvornaya, A.

    2017-01-01

    Resonant laser ionization and spectroscopy are widely used techniques at radioactive ion beam facilities to produce pure beams of exotic nuclei and measure the shape, size, spin and electromagnetic multipole moments of these nuclei. However, in such measurements it is difficult to combine a high efficiency with a high spectral resolution. Here we demonstrate the on-line application of atomic laser ionization spectroscopy in a supersonic gas jet, a technique suited for high-precision studies of the ground- and isomeric-state properties of nuclei located at the extremes of stability. The technique is characterized in a measurement on actinium isotopes around the N=126 neutron shell closure. A significant improvement in the spectral resolution by more than one order of magnitude is achieved in these experiments without loss in efficiency. PMID:28224987

  7. Laser spectroscopy of gas confined in nanoporous materials

    CERN Document Server

    Svensson, Tomas

    2009-01-01

    We show that high-resolution laser spectroscopy can probe surface interactions of gas confined in nano-cavities of porous materials. We report on strong line broadening and unfamiliar lineshapes due to tight confinement, as well as signal enhancement due to multiple photon scattering. This new domain of laser spectroscopy constitute a challenge for the theory of collisions and spectroscopic lineshapes, and open for new ways of analyzing porous materials and processes taking place therein.

  8. Master on Photonics and Laser Technologies: on-line teaching experience

    Science.gov (United States)

    Paredes, Ángel; Michinel, Humberto; Salgueiro, José R.; Vázquez-Dorrío, Benito; Yáñez, Armando; Arines, Justo; Flores-Arias, M. Teresa

    2014-07-01

    The Galician Universitary System (SUG) in the framework of the European studies under the Bologna process presents a huge number of Masters courses. In this work we present the teaching framework of the Science Masters on "Photonics and Laser Technologies", coordinated by the University of Vigo (UVigo) and involving the three Universities of Galicia: University of Vigo (UVigo), University of Santiago de Compostela (USC) and University of Coruña (UdC). The aim of this work is to show how teaching at this Masters is carried out using an online platform so that the whole expertise of all the three Universities can be properly exploited and the geographic dispersion of lecturers and students overcame. The used platform permits the students to attend the lessons from their own Universities without wasting time and money on traveling. Besides, each lecturer can teach from his/her own University, allowing the combination of this activity with other professional and scientific duties. Thanks to this tool, the Masters could host students that followed the lessons from other different countries. The platform has been used for lectures, seminar classes, examinations, conferences and coordination activities between teachers and students.

  9. 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.

  10. Laser frequency stabilization based on Sagnac interferometric spectroscopy

    Institute of Scientific and Technical Information of China (English)

    Hui Yan; Guoqing Yang; Jin Wang; Mingsheng Zhan

    2008-01-01

    @@ A simple method based on Sagnac interferometric spectroscopy (SIS) is applied for frequency stabilization of diode lasers. Sagnac interferometric spectra of rubidium vapor are investigated both theoretically and experimentally. The interference signal at the output of the Sagnac interferometer displays a sharp dispersion feature near the atomic resonance. This dispersion curve is used as the feedback error signal to stabilize the laser frequency. Linewidth of a diode laser is stabilized down to 1 MHz by this modulation-free method.

  11. Trace metal mapping by laser-induced breakdown spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Kaiser, Jozef [ORNL; Novotny, Dr. Karel [Masaryk University; Hrdlicka, A [Brno University of Technology, Czech Republic; Malina, R [Brno University of Technology, Czech Republic; Hartl, M [Brno University of Technology, Czech Republic; Kizek, R [Mendel University of Brno; Adam, V [Mendel University of Brno

    2012-01-01

    Abstract: Laser-Induced Breakdown Spectroscopy (LIBS) is a sensitive optical technique capable of fast multi-elemental analysis of solid, gaseous and liquid samples. The potential applications of lasers for spectrochemical analysis were developed shortly after its invention; however the massive development of LIBS is connected with the availability of powerful pulsed laser sources. Since the late 80s of 20th century LIBS dominated the analytical atomic spectroscopy scene and its application are developed continuously. Here we review the utilization of LIBS for trace elements mapping in different matrices. The main emphasis is on trace metal mapping in biological samples.

  12. Frequency Comb Assisted Broadband Precision Spectroscopy with Cascaded Diode Lasers

    CERN Document Server

    Liu, Junqiu; Pfeiffer, Martin H P; Kordts, Arne; Kamel, Ayman N; Guo, Hairun; Geiselmann, Michael; Kippenberg, Tobias J

    2016-01-01

    Frequency comb assisted diode laser spectroscopy, employing both the accuracy of an optical frequency comb and the broad wavelength tuning range of a tunable diode laser, has been widely used in many applications. In this letter we present a novel method using cascaded frequency agile diode lasers, which allows extending the measurement bandwidth to 37.4 THz (1355 to 1630 nm) at MHz resolution with scanning speeds above 1 THz/s. It is demonstrated as a useful tool to characterize a broadband spectrum for molecular spectroscopy and in particular it enables to characterize the dispersion of integrated microresonators up to the fourth order.

  13. [Study on CO2 measurement using tunable multi-mode diode laser absorption spectroscopy].

    Science.gov (United States)

    Gao, Guang-Zhen; Chen, Bao-Xue; Hu, Bo; Long, Xiu-Hui; Li, Ai-Ping; Li, Rong

    2013-12-01

    Tunable diode laser absorption spectroscopy (TDLAS) technology is a kind of fast time response, large-range, continuous on-line monitoring gas detection technique. It is the mainstream technology of gas detection. In this paper the multimode laser diode was used as light source. Multi-mode laser combined with correlation spectroscopy can improve the test reliability and stability. It can also conquer the problem of the central wavelength change of the single mode diode laser due to thermal or mechanical fluctuations in durable working process. A FP laser was used as the light source in this research. A multi-mode diode laser system based on correlation spectroscopy and wavelength modulation spectroscopy (TMDL-COSPEC-WMS) was used to measure carbon dioxide in ambient air around 1 570 nm. The carbon dioxide concentrations were derived from the relationship between the normalized WMS-2f signal peak heights of the measurement and reference signals which selected based on high signal to noise ratio and correlation coefficient. All measurements were performed with controlled carbon dioxide and nitrogen mixtures in which carbon dioxide concentrations range from 0. 6% to 30%. The calculation results showed that there was a high linear relationship between the measured and actual carbon dioxide concentration, the linearity was 0. 998 7 and the fitted slope was 1. 061+/-0. 016 8 respectively over the tested range. A detection limit of 335 ppm m was achieved. The standard deviation of 0. 036 7% was achieved using 20 successive measurements with each measurement time taking approximately 10 s during 20 minutes, which demonstrated good stability of the system. Good agreements between the measurements of the system and actual values confirm the accuracy and potential utility of the system for carbon dioxide detection.

  14. Potential of on-line visible and near infrared spectroscopy for measurement of pH for deriving variable rate lime recommendations.

    Science.gov (United States)

    Tekin, Yücel; Kuang, Boyan; Mouazen, Abdul M

    2013-08-08

    This paper aims at exploring the potential of visible and near infrared (vis-NIR) spectroscopy for on-line measurement of soil pH, with the intention to produce variable rate lime recommendation maps. An on-line vis-NIR soil sensor set up to a frame was used in this study. Lime application maps, based on pH predicted by vis-NIR techniques, were compared with maps based on traditional lab-measured pH. The validation of the calibration model using off-line spectra provided excellent prediction accuracy of pH (R2 = 0.85, RMSEP = 0.18 and RPD = 2.52), as compared to very good accuracy obtained with the on-line measured spectra (R2 = 0.81, RMSEP = 0.20 and RPD = 2.14). On-line predicted pH of all points (e.g., 2,160) resulted in the largest overall field virtual lime requirement (1.404 t), as compared to those obtained with 16 validation points off-line prediction (0.28 t), on-line prediction (0.14 t) and laboratory reference measurement (0.48 t). The conclusion is that the vis-NIR spectroscopy can be successfully used for the prediction of soil pH and for deriving lime recommendations. The advantage of the on-line sensor over sampling with limited number of samples is that more detailed information about pH can be obtained, which is the reason for a higher but precise calculated lime recommendation rate.

  15. Spectroscopy of Nd-doped laser materials

    Science.gov (United States)

    George, Simi A.; Hayden, Joseph S.

    2014-02-01

    Laser design codes utilize laser properties provided by materials manufacturers for performance modeling. Large scale manufacturing of materials during compositional developments for a particular laser design is not economically feasible. Nevertheless, the laser properties derived from the available sample volumes must be reliable and reproducible. In recent years, as a result of the renewed interest in novel glasses for ultrafast laser applications, SCHOTT has developed improved measurements and methodologies for providing the most accurate information possible to laser scientists. Even though the J-O method is robust and time tested for the spectroscopic characterization of Nd3+, the accuracy of the results requires reliable measurements. This paper outlines the J-O approximation for manifold to manifold transitions, measurements needed, and some of the pitfalls to watch for during the collection of data for Nd-doped materials.

  16. Development of narrowband lasers for spectroscopy of antiprotonic atoms

    Directory of Open Access Journals (Sweden)

    Hori M.

    2014-03-01

    Full Text Available We review some lasers developed by the ASACUSA collaboration of CERN, to carry out spectroscopy of antiprotonic helium atoms. These lasers were based on the technique of continuous-wave injection seeding of pulsed lasers. The laser output covered the wavelength regions 264–1154 nm, with peak powers of ~ 1 MW and spectral resolutions of 6–40 MHz. The devices were recently used to measure the transition frequencies of antiprotonic helium atoms to a fractional precision of several parts in ~ 109.

  17. On-line detection of heavy metals and brominated flame retardants in technical polymers with laser-induced breakdown spectrometry

    Science.gov (United States)

    Stepputat, Michael; Noll, Reinhard

    2003-10-01

    The use of laser-induced breakdown spectrometry (LIBS) for the analysis of heavy metals and brominated flame retardants in end-of-life waste electric and electronic equipment (EOL-WEEE) pieces is investigated. Single- and double-pulse plasma excitation as well as the influence of detection parameters is studied to yield a parameter field with improved sensitivity and limits of detection. A LIBS analyzer was set up as an on-line measuring unit to detect heavy metals and brominated flame retardants in moving EOL-WEEE pieces in an automatic sorting line. An autofocusing unit with an adjustment range of 50 mm was incorporated to permit measurements of objects that pass by a LIBS analyzer with their surfaces at various distances from it. Tests with EOL-WEEE monitor housings on the conveyor belt of a pilot sorting system successfully demonstrated the capability of the LIBS analyzer to quantify the concentration of hazardous elements in real waste EOL-WEEE pieces.

  18. Polarization-enhanced absorption spectroscopy for laser stabilization.

    Science.gov (United States)

    Kunz, Paul D; Heavner, Thomas P; Jefferts, Steven R

    2013-11-20

    We demonstrate a variation of pump-probe spectroscopy that is particularly useful for laser frequency stabilization. The polarization-enhanced absorption spectroscopy (POLEAS) signal provides a significant improvement in signal-to-noise ratio over saturated absorption spectroscopy (SAS) for the important and commonly used atomic cycling transitions. The improvements can directly increase the short-term stability of a laser frequency lock, given sufficient servo loop bandwidth. The long-term stability of the POLEAS method, which is limited by environmental sensitivities, is comparable to that of SAS. The POLEAS signal is automatically Doppler-free, without requiring a separate Doppler subtraction beam, and lends itself to straightforward compact packaging. Finally, by increasing the amplitude of the desired (cycling) peak, while reducing the amplitude of all other peaks in the manifold, the POLEAS method eases the implementation of laser auto-locking schemes.

  19. Laser spectroscopy of trapped Th^3+ ions

    Science.gov (United States)

    Steele, Adam; Campbell, Corey; Churchill, Layne; Depalatis, Michael; Naylor, David; Kuzmich, Alex; Chapman, Michael

    2008-05-01

    We are applying the techniques of laser cooling and ion trapping to investigate the low lying nuclear isomeric state in ^229Th. We will confine Th^3+ atoms in an RF trap [1] and sympathetically cool them with barium ions. The ions are produced by laser ablation from a thorium metal target by the third harmonic of a Q-switched YAG laser. Using mass-spectroscopic techniques we separate out the Th^3+ ions from the plume of ablation products. We once trapped we will observe fluorescence from the trapped ions using transitions at 984 nm and 690 nm. [1] Peik E. and Tamm Chr., Europhysics Letters, 61 (2) (2003)

  20. Laser frequency stabilization by magnetically assisted rotation spectroscopy

    Science.gov (United States)

    Krzemień, Leszek; Brzozowski, Krzysztof; Noga, Andrzej; Witkowski, Marcin; Zachorowski, Jerzy; Zawada, Michał; Gawlik, Wojciech

    2011-03-01

    We present a method of Doppler-free laser frequency stabilization based on magnetically assisted rotation spectroscopy (MARS) which combines the Doppler-free velocity-selective optical pumping (VSOP) and magnetic rotation spectroscopy. The stabilization is demonstrated for the atomic rubidium transitions at 780 nm. The proposed method is largely independent of stray magnetic fields and does not require any modulation of the laser frequency. Moreover, the discussed method allows one to choose between locking the laser exactly to the line center, or with a magnetically-controlled shift to an arbitrary frequency detuned by up to several natural linewidths. This feature is useful in many situations, e.g. for laser cooling experiments. In addition to presenting the principle of the method, its theoretical background and peculiarities inherent to the repopulation VSOP are discussed.

  1. Compositional Analysis of Drugs by Laser-Induced Breakdown Spectroscopy

    Science.gov (United States)

    Beldjilali, S. A.; Axente, E.; Belasri, A.; Baba-Hamed, T.; Hermann, J.

    2017-07-01

    The feasibility of the compositional analysis of drugs by calibration-free laser-induced breakdown spectroscopy (LIBS) was investigated using multivitamin tablets as a sample material. The plasma was produced by a frequencyquadrupled Nd:YAG laser delivering UV pulses with a duration of 5 ns and an energy of 12 mJ, operated at a repetition rate of 10 Hz. The relative fractions of the elements composing the multivitamin drug were determined by comparing the emission spectrum of the laser-produced plume with the spectral radiance computed for a plasma in a local thermodynamic equilibrium. Fair agreement of the measured fractions with those given by the manufacturer was observed for all elements mentioned in the leafl et of the drug. Additional elements such as Ca, Na, Sr, Al, Li, K, and Si were detected and quantifi ed. The present investigations demonstrate that laser-induced breakdown spectroscopy is a viable technique for the quality control of drugs.

  2. Decay-Assisted Laser Spectroscopy of Neutron-Deficient Francium

    CERN Document Server

    Lynch, K M; Bissell, M L; Budincevic, I; Cocolios, T E; De Groote, R P; De Schepper, S; Fedosseev, V N; Flanagan, K T; Franchoo, S; Garcia Ruiz, R F; Heylen, H; Marsh, B A; Neyens, G; Procter, T J; Rossel, R E; Rothe, S; Strashnov, I; Stroke, H H; Wendt, K D A

    2014-01-01

    This paper reports on the hyperfine-structure and radioactive-decay studies of the neutron-deficient francium isotopes $^{202-206}$Fr performed with the Collinear Resonance Ionization Spectroscopy (CRIS) experiment at the ISOLDE facility, CERN. The high resolution innate to collinear laser spectroscopy is combined with the high efficiency of ion detection to provide a highly-sensitive technique to probe the hyperfine structure of exotic isotopes. The technique of decay-assisted laser spectroscopy is presented, whereby the isomeric ion beam is deflected to a decay spectroscopy station for alpha-decay tagging of the hyperfine components. Here, we present the first hyperfine-structure measurements of the neutron-deficient francium isotopes $^{202-206}$Fr, in addition to the identification of the low-lying states of $^{202,204}$Fr performed at the CRIS experiment.

  3. Laser spectroscopy of gallium isotopes using the ISCOOL RFQ cooler

    CERN Multimedia

    Blaum, K; Kowalska, M; Ware, T; Procter, T J

    2007-01-01

    We propose to study the radioisotopes of gallium (Z=31) by collinear laser spectroscopy using the ISCOOL RFQ ion cooler. The proposed measurements on $^{62-83}$Ga will span both neutron-deficient and neutron-rich isotopes. Of key interest is the suggested development of a proton-skin in the neutron-deficient isotopes. The isotope shifts measured by laser spectroscopy will be uniquely sensitive to this feature. The measurements will also provide a wealth of new information on the gallium nuclear spins, static moments and nuclear charge radii.

  4. Time-resolved laser-induced breakdown spectroscopy of aluminum

    Institute of Scientific and Technical Information of China (English)

    LIU Xian-yun; ZHANG Wei-jun; WANG Zhen-ya; HAO Li-qing; HUANG Ming-qiang; ZHAO Wen-wu; LONG Bo; Zhao Wei

    2008-01-01

    We develop a system to measure the elemental composition of unprepared samples using laser-induced breakdown spectroscopy (LIBS) in our laboratory, which can be used for the determination of elements in solids, liquids and aerosols. A description of the instrumentation, including laser, sample chamber and detection, is followed by a brief discussion. The time-resolved LIBS of aluminum at atmospheric pressure is presented. At the end, the possibilities and later uses of this technique are briefly discussed.

  5. Infrared heterodyne spectroscopy for astronomical purposes. [laser applications

    Science.gov (United States)

    Townes, C. H.

    1978-01-01

    Heterodyne infrared astronomy was carried out using CO2 lasers and some solid state tunable lasers. The best available detectors are mercury cadmium telluride photodiodes. Their quantum efficiencies reach values near 0.5 and in an overall system an effective quantum efficiency, taking into account optical losses and amplifier noise, of about 0.25 was demonstrated. Initial uses of 10 micron heterodyne spectroscopy were for the study of planetary molecular spectra.

  6. LASER CORRELATION SPECTROSCOPY (LCS) AND ITS CLINICAL PERSPECTIVES IN OPHTHALMOLOGY

    OpenAIRE

    Karganov Mikhail; Eskina Erika; Stepanova Maria

    2015-01-01

    The method of laser correlation spectroscopy (LCS) is based on the analysis of the spectrum of quasielastic light scatter during coherent monochromatic laser irradiation of micro-particles in biological fluids (blood serum, urine, oropharyngeal washout fluid, tear fluid etc.). Spectrum provides information on dynamic processes in the analyzed system: translation motion of scattering particles and their orientation and conformation dynamics. Special procedures of cluster analysis make it possi...

  7. Highly sensitive detection using Herriott cell for laser absorption spectroscopy

    Science.gov (United States)

    Zhao, Chongyi; Song, Guangming; Du, Yang; Zhao, Xiaojun; Wang, Wenju; Zhong, Liujun; Hu, Mai

    2016-11-01

    The tunable diode laser absorption spectroscopy combined with the long absorption path technique is a significant method to detect harmful gas. The long optical path could come true by Herriott cell reducing the size of the spectrometers. A 15 cm long Herriott cell with 28.8 m optical absorption path after 96 times reflection was designed that enhanced detection sensitivity of absorption spectroscopy. According to the theory data of calculation, Herriott cell is analyzed and simulated by softwares Matlab and Lighttools.

  8. On-line monitoring the extract process of Fu-fang Shuanghua oral solution using near infrared spectroscopy and different PLS algorithms

    Science.gov (United States)

    Kang, Qian; Ru, Qingguo; Liu, Yan; Xu, Lingyan; Liu, Jia; Wang, Yifei; Zhang, Yewen; Li, Hui; Zhang, Qing; Wu, Qing

    2016-01-01

    An on-line near infrared (NIR) spectroscopy monitoring method with an appropriate multivariate calibration method was developed for the extraction process of Fu-fang Shuanghua oral solution (FSOS). On-line NIR spectra were collected through two fiber optic probes, which were designed to transmit NIR radiation by a 2 mm flange. Partial least squares (PLS), interval PLS (iPLS) and synergy interval PLS (siPLS) algorithms were used comparatively for building the calibration regression models. During the extraction process, the feasibility of NIR spectroscopy was employed to determine the concentrations of chlorogenic acid (CA) content, total phenolic acids contents (TPC), total flavonoids contents (TFC) and soluble solid contents (SSC). High performance liquid chromatography (HPLC), ultraviolet spectrophotometric method (UV) and loss on drying methods were employed as reference methods. Experiment results showed that the performance of siPLS model is the best compared with PLS and iPLS. The calibration models for AC, TPC, TFC and SSC had high values of determination coefficients of (R2) (0.9948, 0.9992, 0.9950 and 0.9832) and low root mean square error of cross validation (RMSECV) (0.0113, 0.0341, 0.1787 and 1.2158), which indicate a good correlation between reference values and NIR predicted values. The overall results show that the on line detection method could be feasible in real application and would be of great value for monitoring the mixed decoction process of FSOS and other Chinese patent medicines.

  9. Sub-kilohertz laser linewidth narrowing using polarization spectroscopy.

    Science.gov (United States)

    Torrance, Joshua S; Sparkes, Ben M; Turner, Lincoln D; Scholten, Robert E

    2016-05-30

    We identify several beneficial characteristics of polarization spectroscopy as an absolute atomic reference for frequency stabilization of lasers, and demonstrate sub-kilohertz laser spectral linewidth narrowing using polarization spectroscopy with high-bandwidth feedback. Polarization spectroscopy provides a highly dispersive velocity-selective absolute atomic reference based on frequency-dependent birefringence in an optically pumped atomic gas. The pumping process leads to dominance of the primary closed transition, suppressing closely-spaced subsidiary resonances which reduce the effective capture range for conventional atomic references. The locking signal is based on subtraction of two orthogonal polarization signals, reducing the effect of laser intensity noise to the shot noise limit. We measure noise-limited servo bandwidth comparable to that of a high-finesse optical cavity without the frequency limit or complexity imposed by optical modulation normally associated with high bandwidth laser frequency stabilization. We demonstrate narrowing to 600±100 Hz laser linewidth using the beatnote between two similarly locked external cavity diode lasers.

  10. Improving the Selectivity of the ISOLDE Resonance Ionization Laser Ion Source and In-Source Laser Spectroscopy of Polonium

    CERN Document Server

    Fink, Daniel Andreas; Jochim, Selim

    Exotic atomic nuclei far away from stability are fascinating objects to be studied in many scientic elds such as atomic-, nuclear-, and astrophysics. Since these are often short-lived isotopes, it is necessary to couple their production with immediate extraction and delivery to an experiment. This is the purpose of the on-line isotope separator facility, ISOLDE, at CERN. An essential aspect of this laboratory is the Resonance Ionization Laser Ion Source (RILIS) because it provides a fast and highly selective means of ionizing the reaction products. This technique is also a sensitive laser-spectroscopy tool for the development and improvement of electron excitation schemes for the resonant laser photoionization and the study of the nuclear structure or fundamental atomic physics. Each of these aspects of the RILIS applications are subjects of this thesis work: a new device for the suppression of unwanted surface ionized contaminants in RILIS ion beams, known as the Laser Ion Source and Trap (LIST), was impleme...

  11. Near-Infrared Spectroscopy as an Analytical Process Technology for the On-Line Quantification of Water Precipitation Processes during Danhong Injection

    Directory of Open Access Journals (Sweden)

    Xuesong Liu

    2015-01-01

    Full Text Available This paper used near-infrared (NIR spectroscopy for the on-line quantitative monitoring of water precipitation during Danhong injection. For these NIR measurements, two fiber optic probes designed to transmit NIR radiation through a 2 mm flow cell were used to collect spectra in real-time. Partial least squares regression (PLSR was developed as the preferred chemometrics quantitative analysis of the critical intermediate qualities: the danshensu (DSS, (R-3, 4-dihydroxyphenyllactic acid, protocatechuic aldehyde (PA, rosmarinic acid (RA, and salvianolic acid B (SAB concentrations. Optimized PLSR models were successfully built and used for on-line detecting of the concentrations of DSS, PA, RA, and SAB of water precipitation during Danhong injection. Besides, the information of DSS, PA, RA, and SAB concentrations would be instantly fed back to site technical personnel for control and adjustment timely. The verification experiments determined that the predicted values agreed with the actual homologic value.

  12. Two-dimensional fluorescence spectroscopy of laser-produced plasmas

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-08-01

    We use a two-dimensional laser-induced fluorescence spectroscopy technique to measure the coupled absorption and emission properties of atomic species in plasmas produced via laser ablation of solid aluminum targets at atmospheric pressure. Emission spectra from the Al I 394.4 nm and Al I 396.15 nm transitions are measured while a frequency-doubled, continuous-wave, Ti:Sapphire laser is tuned across the Al I 396.15 nm transition. The resulting two-dimensional spectra show the energy coupling between the two transitions via increased emission intensity for both transitions during resonant absorption of the continuous-wave laser at one transition. Time-delayed and gated detection of the emission spectrum is used to isolate the resonantly-excited fluorescence emission from the thermally-excited emission from the plasma. In addition, the tunable continuous-wave laser measures the absorption spectrum of the Al transition with ultra-high resolution after the plasma has cooled, resulting in narrower spectral linewidths than observed in emission spectra. Our results highlight that fluorescence spectroscopy employing continuous-wave laser re-excitation after pulsed laser ablation combines benefits of both traditional emission and absorption spectroscopic methods.

  13. Detection of early caries by laser-induced breakdown spectroscopy

    Science.gov (United States)

    Sasazawa, Shuhei; Kakino, Satoko; Matsuura, Yuji

    2015-07-01

    To improve sensitivity of dental caries detection by laser-induced breakdown spectroscopy (LIBS) analysis, it is proposed to utilize emission peaks in the ultraviolet. We newly focused on zinc whose emission peaks exist in ultraviolet because zinc exists at high concentration in the outer layer of enamel. It was shown that by using ratios between heights of an emission peak of Zn and that of Ca, the detection sensitivity and stability are largely improved. It was also shown that early caries are differentiated from healthy part by properly setting a threshold in the detected ratios. The proposed caries detection system can be applied to dental laser systems such as ones based on Er:YAG-lasers. When ablating early caries part by laser light, the system notices the dentist that the ablation of caries part is finished. We also show the intensity of emission peaks of zinc decreased with ablation with Er:YAG laser light.

  14. Application of antimonide diode lasers in photoacoustic spectroscopy.

    Science.gov (United States)

    Schilt, Stéphane; Vicet, Aurore; Werner, Ralph; Mattiello, Mario; Thévenaz, Luc; Salhi, Abdelmajid; Rouillard, Yves; Koeth, Johannes

    2004-12-01

    First investigations of photoacoustic (PA) spectroscopy (PAS) of methane using an antimonide semiconductor laser are reported. The laser fabrication is made in two steps. The structure is firstly grown by molecular beam epitaxy, then a metallic distributed-feedback (DFB) grating is processed. The laser operates at 2371.6 nm in continuous wave and at room temperature. It demonstrates single-mode emission with typical tuning coefficients of 0.04 nm mA(-1) and 0.2 nm K(-1). PA detection of methane was performed by coupling this laser into a radial PA cell. A detection limit of 20 ppm has been achieved in a preliminary configuration that was not optimised for the laser characteristics.

  15. Laser frequency stabilization and shifting by using modulation transfer spectroscopy

    Science.gov (United States)

    Cheng, Bing; Wang, Zhao-Ying; Wu, Bin; Xu, Ao-Peng; Wang, Qi-Yu; Xu, Yun-Fei; Lin, Qiang

    2014-10-01

    The stabilizing and shifting of laser frequency are very important for the interaction between the laser and atoms. The modulation transfer spectroscopy for the 87Rb atom with D2 line transition F = 2 → F' = 3 is used for stabilizing and shifting the frequency of the external cavity grating feedback diode laser. The resonant phase modulator with electro—optical effect is used to generate frequency sideband to lock the laser frequency. In the locking scheme, circularly polarized pump- and probe-beams are used. By optimizing the temperature of the vapor, the pump- and probe-beam intensity, the laser linewidth of 280 kHz is obtained. Furthermore, the magnetic field generated by a solenoid is added into the system. Therefore the system can achieve the frequency locking at any point in a range of hundreds of megahertz frequency shifting with very low power loss.

  16. Laser-Induced Breakdown Spectroscopy and Chlorophyll a Flourescence Transients

    DEFF Research Database (Denmark)

    Frydenvang, Jens

    of a sufficient quality; something that remains a problem for many in-situ methods. In my PhD, I present my work with two such in-situ methods, Laser-Induced Breakdown Spectroscopy (LIBS) and OJIP transients, the rising part of chlorophyll a fluorescence transients from dark-adapted leaves....

  17. Laser-Induced Breakdown Spectroscopy and Chlorophyll a Flourescence Transients

    DEFF Research Database (Denmark)

    Frydenvang, Jens

    of a sufficient quality; something that remains a problem for many in-situ methods. In my PhD, I present my work with two such in-situ methods, Laser-Induced Breakdown Spectroscopy (LIBS) and OJIP transients, the rising part of chlorophyll a fluorescence transients from dark-adapted leaves....

  18. Laser-Induced Breakdown Spectroscopy of Trace Metals

    Science.gov (United States)

    Simons, Stephen (Technical Monitor); VanderWal, Randall L.; Ticich, Thomas M.; West, Joseph R., Jr.

    2004-01-01

    An alternative approach for laser-induced breakdown spectroscopy (LIBS) determination of trace metal determination in liquids is demonstrated. The limits of detection (LOD) for the technique ranged from 10 ppb to 10 ppm for 15 metals metals (Mg, Al, Si, Ca, Ti, Cr, Fe, Co, Ni, Cu, Zn, As, Cd, Hg, Pb) tested.

  19. Detection of diamond in ore using pulsed laser Raman spectroscopy

    CSIR Research Space (South Africa)

    Lamprecht, GH

    2007-10-01

    Full Text Available The viability of using pulsed laser excited Raman spectroscopy as a method for diamond detection from ore, has been investigated. In this method the spontaneous Stokes Raman signal is used as indicator of diamond, and a dual channel system...

  20. Recent results on neutron rich tin isotopes by laser spectroscopy

    CERN Document Server

    Roussière, B; Crawford, J E; Essabaa, S; Fedosseev, V; Geithner, W; Genevey, J; Girod, M; Huber, G; Horn, R; Kappertz, S; Lassen, J; Le Blanc, F; Lee, J K P; Le Scornet, G; Lettry, Jacques; Mishin, V I; Neugart, R; Obert, J; Oms, J; Ouchrif, A; Peru, S; Pinard, J; Ravn, H L; Sauvage, J; Verney, D

    2001-01-01

    Laser spectroscopy measurements have been performed on neutron rich tin isotopes using the COMPLIS experimental setup. The nuclear charge radii of the even-even isotopes from A=108 to 132 are compared to the results of macroscopic and microscopic calculations. The improvements and optimizations needed to perform the isotope shift measurement on $^{134}$Sn are presented.

  1. Nuclear spins of the isomers /sup 191m-185m/Hg determined by on-line quantum-beat spectroscopy

    CERN Document Server

    Kremmling, H; Fischer, H G; Kluge, H J; Kühl, T; Schüssler, H A

    1979-01-01

    The nuclear spins of the very neutron-deficient /sup 191m-185m/Hg isomers were measured on line at the mass separator ISOLIDE at CERN using pulsed-laser excitation and observation of the time-resolved quantum beats from selected hyperfine-structure states. The spins of these isomers are with I=13/2 equal to those of the long-lived isomers /sup 199m-193m/Hg already known. The persistence of this spin value for eight isomers is explained by the model of rotation-aligned coupling. (12 refs).

  2. Ramsey-comb spectroscopy with intense ultrashort laser pulses

    CERN Document Server

    Morgenweg, Jonas; Eikema, Kjeld S E

    2014-01-01

    Optical frequency combs based on mode-locked lasers have revolutionised the field of metrology and precision spectroscopy by providing precisely calibrated optical frequencies and coherent pulse trains. Amplification of the pulsed output from these lasers is very desirable, as nonlinear processes can then be employed to cover a much wider range of transitions and wavelengths for ultra-high precision, direct frequency comb spectroscopy. Therefore full repetition rate laser amplifiers and enhancement resonators have been employed to produce up to microjoule-level pulse energies. Here we show that the full frequency comb accuracy and resolution can be obtained by using only two frequency comb pulses amplified to the millijoule pulse energy level, orders of magnitude more energetic than what has previously been possible. The novel properties of this approach, such as cancellation of optical light-shift effects, is demonstrated on weak two-photon transitions in atomic rubidium and caesium, thereby improving the fr...

  3. Oxygen measurement by multimode diode lasers employing gas correlation spectroscopy.

    Science.gov (United States)

    Lou, Xiutao; Somesfalean, Gabriel; Chen, Bin; Zhang, Zhiguo

    2009-02-10

    Multimode diode laser (MDL)-based correlation spectroscopy (COSPEC) was used to measure oxygen in ambient air, thereby employing a diode laser (DL) having an emission spectrum that overlaps the oxygen absorption lines of the A band. A sensitivity of 700 ppm m was achieved with good accuracy (2%) and linearity (R(2)=0.999). For comparison, measurements of ambient oxygen were also performed by tunable DL absorption spectroscopy (TDLAS) technique employing a vertical cavity surface emitting laser. We demonstrate that, despite slightly degraded sensitivity, the MDL-based COSPEC-based oxygen sensor has the advantages of high stability, low cost, ease-of-use, and relaxed requirements in component selection and instrument buildup compared with the TDLAS-based instrument.

  4. Laser ablation mass spectroscopy of nineteenth century daguerreotypes

    Energy Technology Data Exchange (ETDEWEB)

    Hogan, Danel L. [Life Sciences Division, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, Tennessee 37831-6125 (United States); Golovlev, Valerie V. [Life Sciences Division, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, Tennessee 37831-6125 (United States); Gresalfi, Michael J. [Life Sciences Division, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, Tennessee 37831-6125 (United States); Chaney, John A. [Life Sciences Division, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, Tennessee 37831-6125 (United States); Feigerle, Charles S. [Life Sciences Division, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, Tennessee 37831-6125 (United States); Miller, John C. [Life Sciences Division, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, Tennessee 37831-6125 (United States); Romer, Grant [International Museum of Photography and Film, George Eastman House, 900 East Ave., Rochester, New York 14607-2298 (United States); Messier, Paul [Boston Art Conservation, 60 Oak Square Ave., Boston, Massachusetts 02135 (United States)

    1999-10-01

    Laser desorption mass spectroscopy has been used to characterize both modern and {approx}150-year-old daguerreotypes. Such investigations are a necessary prelude to attempts to clean them of tarnish and other contaminants by laser ablation of the surface layers. Both positive- and negative-ion time-of-flight spectra were obtained following YAG laser ablation/desorption at 1064, 532, and 355 nm. Major peaks obtained from several daguerreotypes reveal expected elements from the substrate (Ag, Cu) as well as the developing (Hg) and gilding (Au) processes. Silver clusters (Ag{sub n}) may reflect surface desorption of molecules or, alternatively, aggregates formed in the ejection process. Silver sulfide molecules observed from old daguerreotypes are the signature of the tarnishing process. (c) 2000 Society for Applied Spectroscopy.

  5. 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.

  6. Laser correlation spectroscopy for diagnostics gallstone diseases

    Science.gov (United States)

    Korolevich, Alexander N.; Prigun, N. P.; Khairullina, A. Y.; Belsley, M. S.

    2003-10-01

    The method of dynamical spectroscopy the change in sizes of aggregates of bile vesicules caused by different nucleating factors has been investigated. It is shown that the bile vesicule sizes at chronic cholecystites vary from 90-200 nm. In so doing, the presence of a large fraction of bile vesicules characterized, as shown in the paper, by a higher concentration of cholesterol can serve as a criterion for cholestitis acuteness and litogenesis intensity.

  7. Laser spectroscopy and dynamics of transient species

    Science.gov (United States)

    Clouthier, D. J.

    1994-02-01

    Work was done on sub-Doppler spectroscopy of thioformaldehyde, electronic spectrum of FS2 radical, FTIR spectra of the transient molecule formyl chloride (HCOCl and DCOCl), and high-resolution FTIR spectra of the nu(sub 9) (CH2 wag) and nu(sub 5) (CSO symm. stretch) bands of sulfine (H2CSO), a transient species formed in pyrolysis of dimethyl sulfoxide and oxidation of thioformaldehyde.

  8. Control of stopping position of radioactive ion beam in superfluid helium for laser spectroscopy experiments

    Energy Technology Data Exchange (ETDEWEB)

    Yang, X.F., E-mail: yangxf@ribf.riken.jp [School of Physics, Peking University, Chengfu Road, Haidian District, Beijing 100871 (China); RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Furukawa, T. [Dept. of Physics, Tokyo Metropolitan University, 1-1 Minami-Osawa, Hachioji, Tokyo 192-0397 (Japan); Wakui, T. [Cyclotron and Radioisotope Center Tohoku University, 6-3 Aoba, Aramaki, Aoba-ku, Sendai, Miyagi 980-8578 (Japan); Imamura, K. [Dept. of Physics, Meiji University, 1-1-1 Higashi-Mita, Tama-ku, Kawasaki, Kanagawa 214-8571 (Japan); Tetsuka, H. [Dept. of Physics, Tokyo Gakugei University, 4-1-1 Nukuikitamachi, Koganei, Tokyo 184-8501 (Japan); Fujita, T. [Dept. of Physics, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043 (Japan); Yamaguchi, Y. [Dept. of Physics, Meiji University, 1-1-1 Higashi-Mita, Tama-ku, Kawasaki, Kanagawa 214-8571 (Japan); Tsutsui, Y. [Dept. of Physics, Tokyo Gakugei University, 4-1-1 Nukuikitamachi, Koganei, Tokyo 184-8501 (Japan); Mitsuya, Y. [Dept. of Physics, Meiji University, 1-1-1 Higashi-Mita, Tama-ku, Kawasaki, Kanagawa 214-8571 (Japan); Ichikawa, Y. [Dept. of Physics, Tokyo Institute of Technology, 2-12-1 O-Okayama, Meguro, Tokyo152-8551 (Japan); Ishibashi, Y. [RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Dept. of Physics, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8571 (Japan); Yoshida, N.; Shirai, H. [Dept. of Physics, Tokyo Institute of Technology, 2-12-1 O-Okayama, Meguro, Tokyo152-8551 (Japan); Ebara, Y.; Hayasaka, M. [Dept. of Physics, Tokyo Gakugei University, 4-1-1 Nukuikitamachi, Koganei, Tokyo 184-8501 (Japan); Arai, S.; Muramoto, S. [Dept. of Physics, Meiji University, 1-1-1 Higashi-Mita, Tama-ku, Kawasaki, Kanagawa 214-8571 (Japan); Hatakeyama, A. [Dept. of Applied Physics, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo 184-8588 (Japan); Wada, M.; Sonoda, T. [RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); and others

    2013-12-15

    In order to investigate the structure of exotic nuclei with extremely low yields by measuring nuclear spins and moments, a new laser spectroscopy technique – “OROCHI” (Optical Radioisotopes Observation in Condensed Helium as Ion-catcher) has been proposed in recent years. The feasibility of this technique has been demonstrated by means of a considerable amount of offline and online studies of various atoms in superfluid helium. For in-situ laser spectroscopy of atoms in He II, trapping atoms in the observation region of laser is a key step. Therefore, a method which enables us to trap accelerated atoms at a precise position in He II is highly needed for performing experiment. In this work, a technique making use of a degrader, two plastic scintillators and a photon detection system is established for checking the stopping position of beam based on the LISE++ calculation. The method has been tested and verified by on-line experiments with the {sup 84,85,87}Rb beam. Details of the experimental setup, working procedure and testing results of this method are presented.

  9. Laser Spectroscopy Investigations of Materials for Solid State Laser Systems.

    Science.gov (United States)

    1988-02-01

    Experimental geometry for anisotropic self-diffraction expert. Permanent address: Departamento de Optics y Estructura de Is Materia, mints. e refers to the...the helium-neon laser and PMT is the photo- "Permanent address: Departamento de Optics y Estructura de Ia Materia, multiplier tube. The results are sent

  10. On-line optical and X-ray spectroscopies with crystallography: an integrated approach for determining metalloprotein structures in functionally well defined states.

    Science.gov (United States)

    Ellis, Mark J; Buffey, Steven G; Hough, Michael A; Hasnain, S Samar

    2008-09-01

    X-ray-induced redox changes can lead to incorrect assignments of the functional states of metals in metalloprotein crystals. The need for on-line monitoring of the status of metal ions (and other chromophores) during protein crystallography experiments is of growing importance with the use of intense synchrotron X-ray beams. Significant efforts are therefore being made worldwide to combine different spectroscopies in parallel with X-ray crystallographic data collection. Here the implementation and utilization of optical and X-ray absorption spectroscopies on the modern macromolecular crystallography (MX) beamline 10, at the SRS, Daresbury Laboratory, is described. This beamline is equipped with a dedicated monolithic energy-dispersive X-ray fluorescence detector, allowing X-ray absorption spectroscopy (XAS) measurements to be made in situ on the same crystal used to record the diffraction data. In addition, an optical microspectrophotometer has been incorporated on the beamline, thus facilitating combined MX, XAS and optical spectroscopic measurements. By uniting these techniques it is also possible to monitor the status of optically active and optically silent metal centres present in a crystal at the same time. This unique capability has been applied to observe the results of crystallographic data collection on crystals of nitrite reductase from Alcaligenes xylosoxidans, which contains both type-1 and type-2 Cu centres. It is found that the type-1 Cu centre photoreduces quickly, resulting in the loss of the 595 nm peak in the optical spectrum, while the type-2 Cu centre remains in the oxidized state over a much longer time period, for which independent confirmation is provided by XAS data as this centre has an optical spectrum which is barely detectable using microspectrophotometry. This example clearly demonstrates the importance of using two on-line methods, spectroscopy and XAS, for identifying well defined redox states of metalloproteins during

  11. Influence of the gaseous mixture composition on accuracy of molecular iodine on-line detection by laser-induced fluorescence method

    Science.gov (United States)

    Kireev, S. V.; Shnyrev, S. L.

    2016-07-01

    This paper informs on research into the influence of the composition of gaseous mixtures analyzed on the accuracy of on-line molecular iodine detection by laser-induced fluorescence in various gaseous media—in atmospheric air and in technological mixtures formed during reprocessing of spent nuclear fuel. The paper shows that by considering the composition of buffer media and parts of its components, the accuracy of iodine content measurement may be increased in several times.

  12. Apparatus, system, and method for laser-induced breakdown spectroscopy

    Science.gov (United States)

    Effenberger, Jr., Andrew J; Scott, Jill R; McJunkin, Timothy R

    2014-11-18

    In laser-induced breakdown spectroscopy (LIBS), an apparatus includes a pulsed laser configured to generate a pulsed laser signal toward a sample, a constructive interference object and an optical element, each located in a path of light from the sample. The constructive interference object is configured to generate constructive interference patterns of the light. The optical element is configured to disperse the light. A LIBS system includes a first and a second optical element, and a data acquisition module. The data acquisition module is configured to determine an isotope measurement based, at least in part, on light received by an image sensor from the first and second optical elements. A method for performing LIBS includes generating a pulsed laser on a sample to generate light from a plasma, generating constructive interference patterns of the light, and dispersing the light into a plurality of wavelengths.

  13. On-line monitoring of extraction process of Flos Lonicerae Japonicae using near infrared spectroscopy combined with synergy interval PLS and genetic algorithm

    Science.gov (United States)

    Yang, Yue; Wang, Lei; Wu, Yongjiang; Liu, Xuesong; Bi, Yuan; Xiao, Wei; Chen, Yong

    2017-07-01

    There is a growing need for the effective on-line process monitoring during the manufacture of traditional Chinese medicine to ensure quality consistency. In this study, the potential of near infrared (NIR) spectroscopy technique to monitor the extraction process of Flos Lonicerae Japonicae was investigated. A new algorithm of synergy interval PLS with genetic algorithm (Si-GA-PLS) was proposed for modeling. Four different PLS models, namely Full-PLS, Si-PLS, GA-PLS, and Si-GA-PLS, were established, and their performances in predicting two quality parameters (viz. total acid and soluble solid contents) were compared. In conclusion, Si-GA-PLS model got the best results due to the combination of superiority of Si-PLS and GA. For Si-GA-PLS, the determination coefficient (Rp2) and root-mean-square error for the prediction set (RMSEP) were 0.9561 and 147.6544 μg/ml for total acid, 0.9062 and 0.1078% for soluble solid contents, correspondingly. The overall results demonstrated that the NIR spectroscopy technique combined with Si-GA-PLS calibration is a reliable and non-destructive alternative method for on-line monitoring of the extraction process of TCM on the production scale.

  14. Diode laser absorption spectroscopy of lithium isotopes

    Science.gov (United States)

    Olivares, Ignacio E.; González, Iván A.

    2016-10-01

    We study Doppler-limited laser intensity absorption, in a thermal lithium vapor containing 7Li and 6Li atoms in a 9 to 1 ratio, using a narrow-linewidth single-longitudinal-mode tunable external cavity diode laser at the wavelength of 670.8 nm. The lithium vapor was embedded in helium or argon buffer gas. The spectral lineshapes were rigorously predicted for D_1 and D_2 for the lithium 6 and 7 isotope lines using reduced optical Bloch equations, specifically derived, from a density matrix analysis. Here, a detailed comparison is provided of the predicted lineshapes with the measured 7Li-D_2, 7Li-D_1, 6Li-D_2 and 6Li-D_1 lines, in the case of high vapor density and with intensity above the saturation intensity. To our knowledge, this is the first time that such detailed comparison is reported in the open literature. The calculations were also extended to saturated absorption spectra and compared to measured Doppler-free 7Li-D_2 and 6Li-D_2 hyperfine lines.

  15. Characterization of hard coatings produced by laser cladding using laser-induced breakdown spectroscopy technique

    Energy Technology Data Exchange (ETDEWEB)

    Varela, J.A.; Amado, J.M.; Tobar, M.J.; Mateo, M.P.; Yañez, A.; Nicolas, G., E-mail: gines@udc.es

    2015-05-01

    Highlights: • Chemical mapping and profiling by laser-induced breakdown spectroscopy (LIBS) of coatings produced by laser cladding. • Production of laser clads using tungsten carbide (WC) and nickel based matrix (NiCrBSi) powders. • Calibration by LIBS of hardfacing alloys with different WC concentrations. - Abstract: Protective coatings with a high abrasive wear resistance can be obtained from powders by laser cladding technique, in order to extend the service life of some industrial components. In this work, laser clad layers of self-fluxing NiCrBSi alloy powder mixed with WC powder have been produced on stainless steel substrates of austenitic type (AISI 304) in a first step and then chemically characterized by laser-induced breakdown spectroscopy (LIBS) technique. With the suitable laser processing parameters (mainly output power, beam scan speed and flow rate) and powders mixture proportions between WC ceramics and NiCrBSi alloys, dense pore free layers have been obtained on single tracks and on large areas with overlapped tracks. The results achieved by LIBS technique and applied for the first time to the analysis of laser clads provided the chemical composition of the tungsten carbides in metal alloy matrix. Different measurement modes (multiple point analyses, depth profiles and chemical maps) have been employed, demonstrating the usefulness of LIBS technique for the characterization of laser clads based on hardfacing alloys. The behavior of hardness can be explained by LIBS maps which evidenced the partial dilution of some WC spheres in the coating.

  16. Digital control of diode laser for atmospheric spectroscopy

    Science.gov (United States)

    Menzies, R. T.; Rutledge, C. W. (Inventor)

    1985-01-01

    A system is described for remote absorption spectroscopy of trace species using a diode laser tunable over a useful spectral region of 50 to 200 cm(-1) by control of diode laser temperature over range from 15 K to 100 K, and tunable over a smaller region of typically 0.1 to 10 cm(-1) by control of the diode laser current over a range from 0 to 2 amps. Diode laser temperature and current set points are transmitted to the instrument in digital form and stored in memory for retrieval under control of a microprocessor during measurements. The laser diode current is determined by a digital to analog converter through a field effect transistor for a high degree of ambient temperature stability, while the laser diode temperature is determined by set points entered into a digital to analog converter under control of the microprocessor. Temperature of the laser diode is sensed by a sensor diode to provide negative feedback to the temperature control circuit that responds to the temperature control digital to analog converter.

  17. Laser-induced breakdown spectroscopy: A versatile tool for monitoring traces in materials

    Indian Academy of Sciences (India)

    Shiwani Pandhija; A K Rai

    2008-03-01

    Laser-induced breakdown spectroscopy (LIBS) is an emerging technique for simultaneous multi-elemental analysis of solids, liquids and gases with minute or no sample preparation and thus revolutionized the area of on-line analysis technologies. The foundation for LIBS is a solid state, short-pulsed laser that is focused on a sample to generate a high-temperature plasma, and the emitted radiation from the excited atomic and ionic fragments produced within the plasma is characteristic of the elemental composition of the sample that can be detected and analyzed using a suitable optical spectrograph. In the present paper, the applicability of LIBS for different solid samples having homogeneous (silver ornament, aluminum plate) or heterogeneous composition (soil) using nanosecond laser pulses is discussed. Nanosecond pulse laser makes plasma at the sample surface even at very low pulse energies and also allows for precise ablation of the substrate material with little damage to the surrounding area. We have also studied the penetration of different heavy metals inside the soil surface.

  18. [Monitoring of oxygen concentration based on tunable diode laser absorption spectroscopy].

    Science.gov (United States)

    Zhang, Shuai; Dong, Feng-Zhong; Zhang, Zhi-Rong; Wang, Yu; Kan, Rui-Feng; Zhang, Yu-Jun; Liu, Jian-Guo; Liu, Wen-Qing

    2009-10-01

    Oxygen is a widely used important gas in the industrial process. It is very meaningful to on-line monitor the oxygen concentration for the enhancement of combustion efficiency and reduction in environmental pollution. Tunable diode laser absorption spectroscopy (TDLAS) is a highly sensitive, highly selective and fast time response trace gas detection technique. With the features of tunability and narrow linewidth of distributed feedback (DFB) diode laser and by precisely tuning the laser output wavelength to a single isolated absorption line of the gas, TDLAS technique can be utilized to accurately implement gas concentration measurement with very high sensitivity. In the present paper, the authors used a DFB laser was used as the light source, and by employing wavelength modulation method and measuring the second harmonic signal of one absorption line near 760 nm of oxygen molecule, the authors built a system for online monitoring of oxygen concentration. The characteristics of the system are as follows: the scope of detection is 0.01%-20%; detection accuracy is 0.1%, long term stability is 1%.

  19. Advances in Spectroscopy for Lasers and Sensing

    CERN Document Server

    Bartolo, Baldassare; New Development in Optics and Related Fields

    2006-01-01

    This volume presents the Proceedings of "New Development in Optics and Related Fields," held in Erice, Sicily, Italy, from the 6th to the 21st of June, 2005. This meeting was organized by the International School of Atomic and Molecular Spectroscopy of the "Ettore Majorana" Center for Scientific Culture. The purpose of this Institute was to provide a comprehensive and coherent treatment of the new techniques and contemporary developments in optics and related fields. Several lectures of the course addressed directly the technologies required for the detection and identification of chemical and biological threats; other lectures considered the possible applications of new techniques and materials to the detection and identification of such threats. Each lecturer developed a coherent section of the program starting at a somewhat fundamental level and ultimately reaching the frontier of knowledge in the field in a systematic and didactic fashion.

  20. Method for laser spectroscopy of metastable pionic helium atoms

    Energy Technology Data Exchange (ETDEWEB)

    Hori, M., E-mail: Masaki.Hori@mpq.mpg.de; Sótér, A.; Aghai-Khozani, H. [Max-Planck-Institut für Quantenoptik (Germany); Barna, D. [CERN (Switzerland); Dax, A. [Paul Scherrer Institut (Switzerland); Hayano, R. S.; Murakami, Y.; Yamada, H. [University of Tokyo, Department of Physics (Japan)

    2015-08-15

    The PiHe collaboration is currently attempting to carry out laser spectroscopy of metastable pionic helium atoms using the high-intensity π{sup −} beam of the ring cyclotron facility of the Paul Scherrer Institute. These atoms are heretofore hypothetical three-body Coulomb systems each composed of a helium nucleus, a π{sup −} occupying a Rydberg state, and an electron occupying the 1s ground state. We briefly review the proposed method by which we intend to detect the laser spectroscopic signal. This complements our experiments on metastable antiprotonic helium atoms at CERN.

  1. [Tunable diode laser absorption spectroscopy system for trace ethylene detection].

    Science.gov (United States)

    Pan, Wei-Dong; Zhang, Jia-Wei; Dai, Jing-Min; Song, Kai

    2012-10-01

    Tunable diode laser absorption spectroscopy (TDLAS) was characterized by ultra-narrow line width laser and wavelength modulation, which makes it possible to scan a single absorption line. TDLAS has an advantage in trace gas analysis for its high resolution, high sensitivity and quick response. The 1 626.8 nm absorption line of ethylene was selected for detecting by analyzing its absorption line characteristic. The TDLAS system was developed with a white type multi-pass cell, combined with wavelength modulation and harmonic detection. Ethylene concentration ranges from 20 to 1 200 ppmv were tested using this system. The estimated detection limit of the system is 10 ppmv.

  2. Laser photodissociation and spectroscopy of mass-separated biomolecular ions

    CERN Document Server

    Polfer, Nicolas C

    2014-01-01

    This lecture notes book presents how enhanced structural information of biomolecular ions can be obtained from interaction with photons of specific frequency - laser light. The methods described in the book ""Laser photodissociation and spectroscopy of mass-separated biomolecular ions"" make use of the fact that the discrete energy and fast time scale of photoexcitation can provide more control in ion activation. This activation is the crucial process producing structure-informative product ions that cannot be generated with more conventional heating methods, such as collisional activation. Th

  3. Plasma temperature clamping in filamentation laser induced breakdown spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Harilal, Sivanandan S.; Yeak, J.; Phillips, Mark C.

    2015-10-19

    Ultrafast laser filament induced breakdown spectroscopy is a very promising method for remote material detection. We present characteristics of plasmas generated in a metal target by laser filaments in air. Our measurements show that the temperature of the ablation plasma is clamped along the filamentation channel due to intensity clamping in a filament. Nevertheless, significant changes in radiation intensity are noticeable, and this is essentially due to variation in the number density of emitting atoms. The present results also partly explains the reason for the occurrence of atomic plume during fs LIBS in air compared to long-pulse ns LIBS.

  4. Progress in fieldable laser-induced breakdown spectroscopy (LIBS)

    Science.gov (United States)

    Miziolek, Andrzej W.

    2012-06-01

    In recent years there has been great progress in the Laser Induced Breakdown Spectroscopy (LIBS) technology field. Significant advances have been made both in fundamental and applied research as well as in data processing/chemometrics. Improvements in components, most notably lasers/optics and spectrometers are enabling the development of new devices that are suitable for field use. These new commercial devices recently released to the marketplace, as well as ones currently under development, are bringing the potential of LIBS for CBRNE threat analysis into real-world applications.

  5. Precision spectroscopy of hydrogen and femtosecond laser frequency combs.

    Science.gov (United States)

    Hänsch, T W; Alnis, J; Fendel, P; Fischer, M; Gohle, C; Herrmann, M; Holzwarth, R; Kolachevsky, N; Udem, Th; Zimmermann, M

    2005-09-15

    Precision spectroscopy of the simple hydrogen atom has inspired dramatic advances in optical frequency metrology: femtosecond laser optical frequency comb synthesizers have revolutionized the precise measurement of optical frequencies, and they provide a reliable clock mechanism for optical atomic clocks. Precision spectroscopy of the hydrogen 1S-2S two-photon resonance has reached an accuracy of 1.4 parts in 10(14), and considerable future improvements are envisioned. Such laboratory experiments are setting new limits for possible slow variations of the fine structure constant alpha and the magnetic moment of the caesium nucleus mu(Cs) in units of the Bohr magneton mu(B).

  6. Optical fiber sensing based on reflection laser spectroscopy.

    Science.gov (United States)

    Gagliardi, Gianluca; Salza, Mario; Ferraro, Pietro; Chehura, Edmond; Tatam, Ralph P; Gangopadhyay, Tarun K; Ballard, Nicholas; Paz-Soldan, Daniel; Barnes, Jack A; Loock, Hans-Peter; Lam, Timothy T-Y; Chow, Jong H; De Natale, Paolo

    2010-01-01

    An overview on high-resolution and fast interrogation of optical-fiber sensors relying on laser reflection spectroscopy is given. Fiber Bragg-gratings (FBGs) and FBG resonators built in fibers of different types are used for strain, temperature and acceleration measurements using heterodyne-detection and optical frequency-locking techniques. Silica fiber-ring cavities are used for chemical sensing based on evanescent-wave spectroscopy. Various arrangements for signal recovery and noise reduction, as an extension of most typical spectroscopic techniques, are illustrated and results on detection performances are presented.

  7. Optical Fiber Sensing Based on Reflection Laser Spectroscopy

    Directory of Open Access Journals (Sweden)

    Gianluca Gagliardi

    2010-03-01

    Full Text Available An overview on high-resolution and fast interrogation of optical-fiber sensors relying on laser reflection spectroscopy is given. Fiber Bragg-gratings (FBGs and FBG resonators built in fibers of different types are used for strain, temperature and acceleration measurements using heterodyne-detection and optical frequency-locking techniques. Silica fiber-ring cavities are used for chemical sensing based on evanescent-wave spectroscopy. Various arrangements for signal recovery and noise reduction, as an extension of most typical spectroscopic techniques, are illustrated and results on detection performances are presented.

  8. High-resolution laser spectroscopy of nickel isotopes

    CERN Multimedia

    This proposal aims to measure the nuclear ground-state spins, moments and mean-square charge radii of $^{56-71}$Ni using collinear laser spectroscopy. This will enable direct measurements of isotopes in the region of shell closure $^{56}$Ni, structural change $^{68}$Ni and monopole migration beyond N = 40. Optical spectroscopy serves as a detailed probe not only of the changing single-particle behaviour, but also for the study of collective properties such as size and shape. Measurements of the most neutron-rich isotopes available at ISOLDE will critically test models which seek to extrapolate the data to the doubly magic region of $^{78}$Ni.

  9. [The Research for Trace Ammonia Escape Monitoring System Based on Tunable Diode Laser Absorption Spectroscopy].

    Science.gov (United States)

    Zhang, Li-fang; Wang, Fei; Yu, Li-bin; Yan, Jian-hua; Cen, Ke-fa

    2015-06-01

    In order to on-line measure the trace ammonia slip of the commercial power plant in the future, this research seeks to measure the trace ammonia by using tunable diode laser absorption spectroscopy under ambient temperature and pressure, and at different temperatures, and the measuring temperature is about 650 K in the power plant. In recent years lasers have become commercially available in the near-infrared where the transitions are much stronger, and ammonia's spectroscopy is pretty complicated and the overlapping lines are difficult to resolve. A group of ammonia transitions near 4 433.5 cm(-1) in the v2 +v3 combination band have been thoroughly selected for detecting lower concentration by analyzing its absorption characteristic and considering other absorption interference in combustion gases where H2O and CO2 mole fraction are very large. To illustrate the potential for NH3 concentration measurements, predictions for NH3, H2O and CO2 are simultaneously simulated, NH3 absorption lines near 4 433.5 cm(-1) wavelength meet weaker H2O absorption than the commercial NH3 lines, and there is almost no CO2 absorption, all the parameters are based on the HITRAN database, and an improved detection limit was obtained for interference-free NH3 monitoring, this 2.25 μm band has line strengths several times larger than absorption lines in the 1.53 μm band which was often used by NH3 sensors for emission monitoring and analyzing. The measurement system was developed with a new Herriott cell and a heated gas cell realizing fast absorption measurements of high resolution, and combined with direct absorption and wavelenguh modulation based on tunable diode laser absorption spectroscopy at different temperatures. The lorentzian line shape is dominant at ambient temperature and pressure, and the estimated detectivity is approximately 0.225 x 10(-6) (SNR = 1) for the directed absorption spectroscopy, assuming a noise-equivalent absorbance of 1 x 10(-4). The heated cell

  10. Qualitative Analysis of Teeth and Evaluation of Amalgam Elements Penetration into Dental Matrix Using Laser Induced Breakdown Spectroscopy

    Science.gov (United States)

    Gazmeh, Meisam; Bahreini, Maryam; Tavassoli, Seyed Hassan; Asnaashari, Mohammad

    2015-01-01

    Introduction: In this study, laser induced breakdown spectroscopy (LIBS) is used for qualitative analysis of healthy and carious teeth. The technique of laser ablation is receiving increasing attention for applications in dentistry, specifically for the treatment of teeth such as drilling of micro-holes and plaque removal. Methods: A quality-switched (Q-switched) Neodymium-Doped Yttrium Aluminium Garnet (Nd:YAG) laser operating at wavelength of 1064 nm, pulse energy of 90 mJ/pulse, repetition rate of 2Hz and pulse duration of 6 ns was used in this analysis. In the process of ablation a luminous micro-plasma is normally generated which may be exploited for on-line elemental analysis via laser induced breakdown spectroscopy technique. We propose laser induced breakdown spectroscopy as a rapid, in situ and easy method for monitoring drilling process. Results: The results of elemental analysis show the presence of some trace elements in teeth including P, Ca, Mg, Zn, K, Sr, C, Na, H, O and the permeability of some amalgam (teeth filling materials) elements including Hg, Ag, Cu and Sn into dental matrix. Conclusion: This study addresses the ability of LIBS in elemental analysis of teeth and its feasibility in acute identification of healthy and carious teeth during drilling process for future clinical applications. PMID:25987971

  11. Applications of laser-induced gratings to spectroscopy and dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Rohlfing, E.A. [Sandia National Laboratories, Livermore, CA (United States)

    1993-12-01

    This program has traditionally emphasized two principal areas of research. The first is the spectroscopic characterization of large-amplitude motion on the ground-state potential surface of small, transient molecules. The second is the reactivity of carbonaceous clusters and its relevance to soot and fullerene formation in combustion. Motivated initially by the desire to find improved methods of obtaining stimulated emission pumping (SEP) spectra of transients, most of our recent work has centered on the use of laser-induced gratings or resonant four-wave mixing in free-jet expansions. These techniques show great promise for several chemical applications, including molecular spectroscopy and photodissociation dynamics. The author describes recent applications of two-color laser-induced grating spectroscopy (LIGS) to obtain background-free SEP spectra of transients and double resonance spectra of nonfluorescing species, and the use of photofragment transient gratings to probe photodissociation dynamics.

  12. Laser-induced breakdown spectroscopy theory and applications

    CERN Document Server

    Perini, Umberto

    2014-01-01

    This book deals with the Laser-Induced Breakdown Spectroscopy (LIBS), a widely used atomic emission spectroscopy technique for elemental analysis of materials. It is based on the use of a high-power, short pulse laser excitation. The book is divided into two main sections: the first one concerning theoretical aspects of the technique, the second one describing the state of the art in applications of the technique in different scientific/technological areas. Numerous examples of state of the art applications provide the readers an almost complete scenario of the LIBS technique. The LIBS theoretical aspects are reviewed. The book helps the readers who are less familiar with the technique to understand the basic principles. Numerous examples of state of the art applications give an almost complete scenario of the LIBS technique potentiality. These examples of applications may have a strong impact on future industrial utilization. The authors made important contributions to the development of this field.

  13. Laser Materials and Laser Spectroscopy - A Satellite Meeting of IQEC '88

    Science.gov (United States)

    Wang, Zhijiang; Zhang, Zhiming

    1989-03-01

    The Table of Contents for the book is as follows: * Laser Materials * Laser Site Spectroscopy of Transition Metal Ions in Glass * Spectroscopy of Chromium Doped Tunable Laser Materials * Spectroscopic Properties of Nd3+ Ions in LaMgAl11O19 Crystal * Spectral Study and 2.938 μm Laser Emission of Er3+ in the Y3Al5O12 Crystal * Raman-infrared Spectra and Radiationless Relaxation of Laser Crystal NdAl3(BO3)4 * A Study on HB and FLN in BaFCl0.5Br0.5:Sm2+ at 77K * Pair-pumped Upconversion Solid State Lasers * CW Upconversion Laser Action in Neodymium and Erbium doped Solids * Ultra-high Sensitive Upconversion Fluorescence of YbF3 Doped with Trace Tm3+ and Er3+ * The Growth and Properties of NYAB and EYAB Multifunctional Crystal * Study on Fluorescence and Laser Light of Er3+ in Glass * Growth and Properties of Single Crystal Fibers for Laser Materials * A Study on the Quality of Sapphire, Ruby and Ti3+ Doped Sapphire Grown by Temperature Gradient Technique (TGT) and Czochralski Technique (CZ) * The Measurement of Output Property of Ti3+ Al2O3 Laser Crystal * An Xα Study of the Laser Crystal MgF2 : V2+ * Q-switched NAB Laser * Miniature YAG Lasers * Study of High Efficiency {LiF}:{F}^-_2 Color Center Crystals * Study on the Formation Conditions and Optical Properties of (F2+)H Color Center in NaCl:OH- Crystals * Novel Spectroscopic Properties of {LiF}:{F}^+_3 - {F}_2 Mixed Color Centers Laser Crystals * Terraced Substrate Visible GaAlAs Semiconductor Lasers with a Large Optical Cavity * The Temperature Dependence of Gain Spectra, Threshold Current and Auger Recombination in InGaAsP-InP Double Heterojunction Laser diode * Time-resolved Photoluminescence and Energy Transfer of Bound Excitons in GaP:N Crystals * Optical Limiting with Semiconductors * A Critical Review of High-efficiency Crystals for Tunable Lasers * Parametric Scattering in β - BaB2O4 Crystal Induced by Picosecond Pulses * Generation of Picosecond Pulses at 193 nm by Frequency Mixing in β - BaB2O4

  14. Computational Laser Spectroscopy in a Biological Tissue

    Directory of Open Access Journals (Sweden)

    M. Gantri

    2010-01-01

    Full Text Available We present a numerical spectroscopic study of visible and infrared laser radiation in a biological tissue. We derive a solution of a general two-dimensional time dependent radiative transfer equation in a tissue-like medium. The used model is suitable for many situations especially when the external source is time-dependent or continuous. We use a control volume-discrete ordinate method associated with an implicit three-level second-order time differencing scheme. We consider a very thin rectangular biological-tissue-like medium submitted to a visible or a near infrared light sources. The RTE is solved for a set of different wavelength source. All sources are assumed to be monochromatic and collimated. The energetic fluence rate is computed at a set of detector points on the boundaries. According to the source type, we investigate either the steady-state or transient response of the medium. The used model is validated in the case of a heterogeneous tissue-like medium using referencing experimental results from the literature. Also, the developed model is used to study changes on transmitted light in a rat-liver tissue-like medium. Optical properties depend on the source wavelength and they are taken from the literature. In particular, light-transmission in the medium is studied for continuous wave and for short pulse.

  15. A Simple LIBS (Laser-Induced Breakdown Spectroscopy) Laboratory Experiment to Introduce Undergraduates to Calibration Functions and Atomic Spectroscopy

    Science.gov (United States)

    Chinni, Rosemarie C.

    2012-01-01

    This laboratory experiment introduces students to a different type of atomic spectroscopy: laser-induced breakdown spectroscopy (LIBS). LIBS uses a laser-generated spark to excite the sample; once excited, the elemental emission is spectrally resolved and detected. The students use LIBS to analyze a series of standard synthetic silicate samples…

  16. A Simple LIBS (Laser-Induced Breakdown Spectroscopy) Laboratory Experiment to Introduce Undergraduates to Calibration Functions and Atomic Spectroscopy

    Science.gov (United States)

    Chinni, Rosemarie C.

    2012-01-01

    This laboratory experiment introduces students to a different type of atomic spectroscopy: laser-induced breakdown spectroscopy (LIBS). LIBS uses a laser-generated spark to excite the sample; once excited, the elemental emission is spectrally resolved and detected. The students use LIBS to analyze a series of standard synthetic silicate samples…

  17. Application of Laser Correlation Spectroscopy for Measuring Virus Size.

    Science.gov (United States)

    Nikiforov, V N; Vinogradov, S E; Ivanov, A V; Efremova, E V; Kalnina, L B; Bychenko, A B; Tentsov, Yu Yu; Manykin, A A

    2016-05-01

    Dynamic light scattering method or laser correlation spectroscopy was applied to evaluation of the size of viruses. We measured correlation functions of the light scattered by human immunodeficiency viruses (HIV) and hepatitis A viruses (HAV) and found that size of HIV-1 (subtype A and B) and HAV virions were 104 nm and 28 nm, respectively. Comparison of these findings with electron microscopy data for fixed samples of the same viruses showed good agreement of the results.

  18. Laser-Induced Breakdown Spectroscopy: Fundamentals, Applications, and Challenges

    OpenAIRE

    Anabitarte, F.; Cobo, A.; J. M. Lopez-Higuera

    2012-01-01

    Laser-induced breakdown spectroscopy (LIBS) is a technique that provides an accurate in situ quantitative chemical analysis and, thanks to the developments in new spectral processing algorithms in the last decade, has achieved a promising performance as a quantitative chemical analyzer at the atomic level. These possibilities along with the fact that little or no sample preparation is necessary have expanded the application fields of LIBS. In this paper, we review the state of the ar...

  19. Precision atomic beam density characterization by diode laser absorption spectroscopy

    Science.gov (United States)

    Oxley, Paul; Wihbey, Joseph

    2016-09-01

    We provide experimental and theoretical details of a simple technique to determine absolute line-of-sight integrated atomic beam densities based on resonant laser absorption. In our experiments, a thermal lithium beam is chopped on and off while the frequency of a laser crossing the beam at right angles is scanned slowly across the resonance transition. A lock-in amplifier detects the laser absorption signal at the chop frequency from which the atomic density is determined. The accuracy of our experimental method is confirmed using the related technique of wavelength modulation spectroscopy. For beams which absorb of order 1% of the incident laser light, our measurements allow the beam density to be determined to an accuracy better than 5% and with a precision of 3% on a time scale of order 1 s. Fractional absorptions of order 10-5 are detectable on a one-minute time scale when we employ a double laser beam technique which limits laser intensity noise. For a lithium beam with a thickness of 9 mm, we have measured atomic densities as low as 5 × 104 atoms cm-3. The simplicity of our technique and the details we provide should allow our method to be easily implemented in most atomic or molecular beam apparatuses.

  20. Spectroscopy of laser-produced plasmas: Setting up of high-performance laser-induced breakdown spectroscopy system

    Indian Academy of Sciences (India)

    V K Unnikrishnan; Kamlesh Alti; Rajesh Nayak; Rodney Bernard; V B Kartha; C Santhosh; G P Gupta; B M Suri

    2010-12-01

    It is a well-known fact that laser-induced breakdown spectroscopy (LIBS) has emerged as one of the best analytical techniques for multi-elemental compositional analysis of samples. We report assembling and optimization of LIBS set up using high resolution and broad-range echelle spectrograph coupled to an intensified charge coupled device (ICCD) to detect and quantify trace elements in environmental and clinical samples. Effects of variations of experimental parameters on spectroscopy signals of copper and brass are reported. Preliminary results of some plasma diagnostic calculations using recorded time-resolved optical emission signals are also reported for brass samples.

  1. BaH molecular spectroscopy with relevance to laser cooling

    Science.gov (United States)

    Tarallo, M. G.; Iwata, G. Z.; Zelevinsky, T.

    2016-03-01

    We describe a simple experimental apparatus for laser ablation of barium monohydride (BaH) molecules and the study of their rovibrational spectra relevant to direct laser cooling. BaH is a promising candidate for laser cooling and ultracold fragmentation, both of which are precursors to novel experiments in many-body physics and precision measurement. We present a detailed analysis of the properties of ablation plumes that can improve the understanding of surface ablation and deposition technologies. A range of absorption spectroscopy and collisional thermalization regimes has been studied. We directly measured the Franck-Condon factor of the B 2Σ+(v'=0 ) ←X 2Σ+(v''=1 ) cycling transition. Prospects for production of a high luminosity cryogenic BaH beam are outlined.

  2. Laser Induced Fluorescence Spectroscopy of IrN

    Institute of Scientific and Technical Information of China (English)

    H. F. Pang; A. S. C. Cheung

    2009-01-01

    High resolution laser induced fluorescence spectra of IrN in the spectral region between 394and 520 nm were recorded using laser vaporization/reaction free jet expansion and laser induced fluorescence spectroscopy. Seven new vibronic transition bands were observed and analyzed. TwoΩ=1 and five Ω=0 new states were identified. Least squares fit of rotationally resolved transition lines yielded accurate molecular constants for the upper states. Spectra of isotopic molecules were observed, which provided confirmation for the vibrational assignment. Comparison of the observed electronic states of IrB, IrC, and IrN provides a good understanding of the chemical bonding of this group of molecules.

  3. BaH molecular spectroscopy with relevance to laser cooling

    CERN Document Server

    Tarallo, M G; Zelevinsky, T

    2015-01-01

    We describe a simple experimental apparatus for laser ablation of barium monohydride (BaH) molecules and the study of their rovibrational spectra that are relevant to direct laser cooling. We present a detailed analysis of the properties of ablation plumes that can improve the understanding of surface ablation and deposition technologies. A range of absorption spectroscopy and collisional thermalization regimes has been studied. We directly measured the Franck-Condon factor of the $\\mathrm{B}^2\\Sigma^+(v'=0)\\leftarrow\\mathrm{X}^2\\Sigma^+(v"=1)$ transition. Prospects for production of a high luminosity cryogenic BaH beam are outlined. This molecule is a promising candidate for laser cooling and ultracold fragmentation, both of which are precursors to novel experiments in many-body physics and precision measurement.

  4. Preliminary evaluation of laser-induced breakdown spectroscopy for tissue classification

    Energy Technology Data Exchange (ETDEWEB)

    Yueh Fangyu [Institute for Clean Energy Technology, Mississippi State University, Starkville, MS 39759 (United States); Zheng Hongbo [Department of Applied Physics, Nanjing University of Technology, Nanjing, Jiangsu, 210009 (China); Singh, Jagdish P., E-mail: singh@icet.msstate.ed [Institute for Clean Energy Technology, Mississippi State University, Starkville, MS 39759 (United States); Burgess, Shane [College of Veterinary Medicine, Mississippi State University, Mississippi State, MS 39762 (United States)

    2009-10-15

    Laser-induced breakdown spectroscopy (LIBS) is an on-line, real-time technology that can produce immediate information about the elemental contents of tissue samples. We have previously shown that LIBS may be used to distinguish cancerous from non-cancerous tissue. In this work, we study LIBS spectra produced from chicken brain, lung, spleen, liver, kidney and skeletal muscle. Different data processing techniques were used to study if the information contained in these LIBS spectra is able to differentiate between different types of tissue samples and then identify unknown tissues. We have demonstrated a clear distinguishing between each of the known tissue types with only 21 selected analyte lines from each observed LIBS spectrum. We found that in order to produce an analytical model to work well with new sample we need to have representative training data to cover a wide range of spectral variation due to experimental or environmental changes.

  5. Photoacoustic Spectroscopy with Quantum Cascade Lasers for Trace Gas Detection

    Directory of Open Access Journals (Sweden)

    Gaetano Scamarcio

    2006-10-01

    Full Text Available Various applications, such as pollution monitoring, toxic-gas detection, noninvasive medical diagnostics and industrial process control, require sensitive and selectivedetection of gas traces with concentrations in the parts in 109 (ppb and sub-ppb range.The recent development of quantum-cascade lasers (QCLs has given a new aspect toinfrared laser-based trace gas sensors. In particular, single mode distributed feedback QCLsare attractive spectroscopic sources because of their excellent properties in terms of narrowlinewidth, average power and room temperature operation. In combination with these lasersources, photoacoustic spectroscopy offers the advantage of high sensitivity and selectivity,compact sensor platform, fast time-response and user friendly operation. This paper reportsrecent developments on quantum cascade laser-based photoacoustic spectroscopy for tracegas detection. In particular, different applications of a photoacoustic trace gas sensoremploying a longitudinal resonant cell with a detection limit on the order of hundred ppb ofozone and ammonia are discussed. We also report two QC laser-based photoacousticsensors for the detection of nitric oxide, for environmental pollution monitoring andmedical diagnostics, and hexamethyldisilazane, for applications in semiconductormanufacturing process.

  6. Analysis of Pulverized Coal by Laser-Induced Breakdown Spectroscopy

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Laser-induced breakdown spectroscopy (LIBS) has been used to detect atomic species in various environments. The quantitative analysis (C, H, O, N and S) of representative coal samples are being carried out with LIBS, and the effects of particle size are analyzed.A powerful pulse Nd:YAG laser is focused on the coal sample at atmosphere pressure, and the emission spectra from laser-induced plasmas are measured by time-resolved spectroscopy, and the intensity of analyzed spectral lines is obtained through observing the laser plasma with a delay time of 0.4μs. The experimental results show that the slope of calibration curve is nearly 1 when the concentration of the analyzed element is relatively low, and the slope of curve is nearly 0.5 when the concentration of C is higher than other elements. In addition, using the calibration-free model without self-absorption effect, the results show that the decreasing of particle size leads to an increase of the plasma temperature.

  7. Fibre lasers for photo-acoustic gas spectroscopy

    Science.gov (United States)

    Arsad, Norhana; Stewart, George

    2011-05-01

    We report here on the use of fiber lasers for recovery of gas absorption line shapes by photo-acoustic spectroscopy. We demonstrate the principle of operation using an erbium-doped fiber, stabilized using a length of un-pumped doped fibre as a saturable absorber. Intensity modulation of the laser output for phase sensitive detection is performed by modulation of the pump current while the wavelength is scanned through the absorption line by a PZT on a fibre Bragg grating. This avoids the distortions that arise in recovered signals due to simultaneous wavelength and intensity modulation, as is the case with conventional DFB diode lasers. Furthermore, the near zero off-line signals with photo-acoustic spectroscopy means that high modulation indices can be used with simple intensity modulation of the fiber laser output. The modulation frequency is set to the acoustic resonance frequency of the gas cell and measurements are made on the P17 absorption line of acetylene at 1535.39nm showing good agreement with the theoretical line-shape profile.

  8. [Measurement of oxygen concentration using multimode diode laser absorption spectroscopy].

    Science.gov (United States)

    Gao, Guang-zhen; Cai, Ting-dong; Hu, Bo; Jia, Tian-jun

    2015-01-01

    Tunable diode laser absorption spectroscopy (TDLAS) is a widely used technique for high sensitivity, good selectivity and fast response. It is widely used in environment monitoring, industrial process control and biomedical sensing. In order to overcome the drawbacks of TDLAS including high cost, poor stability and center wavelength shift problem. A multi-mode diode laser system based on correlation spectroscopy and wavelength modulation spectroscopy (TMDL-COSPEC-WMS) was used to measure O2 concentration near 760nm at the 1%~30% range of near room temperature. During the experiment, the light is splitter into two beams, respectively through the sample and measuring cell, two receiving optical signal collection containing gas concentration information sent back stage treatment, invert the oxygen concentration through correlation and ratio between measured signal and reference signal, the correlation spectroscopy harmonic detection technique is used to improve the stability of the system and the signal to noise ratio. The result showed that, there was a good linear relationship between the measured oxygen concentration and the actual concentration value. A detection limit of 280 pmm. m in the 1 atmospheric which approved of the same sample. A continuous measurement for oxygen with the standard deviation of 0. 056% in ambient air during approximately 30 minutes confirms the stability and the capability of the system. The design of the system includes soft and hardware can meet the needs of oxygen online monitoring. The experimental device is simple and easy to use, easy to complex environment application.

  9. Elemental profiling of laser cladded multilayer coatings by laser induced breakdown spectroscopy and energy dispersive X-ray spectroscopy

    Science.gov (United States)

    Lednev, V. N.; Sdvizhenskii, P. A.; Filippov, M. N.; Grishin, M. Ya.; Filichkina, V. A.; Stavertiy, A. Ya.; Tretyakov, R. S.; Bunkin, A. F.; Pershin, S. M.

    2017-09-01

    Multilayer tungsten carbide wear resistant coatings were analyzed by laser induced breakdown spectroscopy (LIBS) and energy dispersive X-ray (EDX) spectroscopy. Coaxial laser cladding technique was utilized to produce tungsten carbide coating deposited on low alloy steel substrate with additional inconel 625 interlayer. EDX and LIBS techniques were used for elemental profiling of major components (Ni, W, C, Fe, etc.) in the coating. A good correlation between EDX and LIBS data was observed while LIBS provided additional information on light element distribution (carbon). A non-uniform distribution of tungsten carbide grains along coating depth was detected by both LIBS and EDX. In contrast, horizontal elemental profiling showed a uniform tungsten carbide particles distribution. Depth elemental profiling by layer-by-layer LIBS analysis was demonstrated to be an effective method for studying tungsten carbide grains distribution in wear resistant coating without any sample preparation.

  10. Laser absorption spectroscopy based on a broadband external cavity quantum cascade laser

    Science.gov (United States)

    Sun, Juan; Liu, Ningwu; Deng, Hao; Ding, Junya; Sun, Jiancha; Zhang, Lei; Li, Jingsong

    2017-02-01

    A tunable diode laser absorption spectroscopy (TDLAS) system based on a broad band external cavity quantum cascade laser (ECQCL) near 7.78 μm was used to study volatile organic compounds (VOCs) measurements. Instead of using a standard infrared mercury cadmium telluride (MCT) detector, a quartz crystal tuning fork (QCTF) as a light detector was successfully used for laser signal detection. Fast Fourier transform (FFT) was used to extract vibration intensity information of QCTF. Primary results indicate that the new developed system has a good reproducibility, and a good agreement was obtained by comparing with data taken from standard spectroscopic database.

  11. On-line application of near-infrared spectroscopy for monitoring water levels in parts per million in a manufacturing-scale distillation process.

    Science.gov (United States)

    Lambertus, Gordon; Shi, Zhenqi; Forbes, Robert; Kramer, Timothy T; Doherty, Steven; Hermiller, James; Scully, Norma; Wong, Sze Wing; LaPack, Mark

    2014-01-01

    An on-line analytical method based on transmission near-infrared spectroscopy (NIRS) for the quantitative determination of water concentrations (in parts per million) was developed and applied to the manufacture of a pharmaceutical intermediate. Calibration models for water analysis, built at the development site and applied at the manufacturing site, were successfully demonstrated during six manufacturing runs at a 250-gallon scale. The water measurements will be used as a forward-processing control point following distillation of a toluene product solution prior to use in a Grignard reaction. The most significant impact of using this NIRS-based process analytical technology (PAT) to replace off-line measurements is the significant reduction in the risk of operator exposure through the elimination of sampling of a severely lachrymatory and mutagenic compound. The work described in this report illustrates the development effort from proof-of-concept phase to manufacturing implementation.

  12. Indirect absorption spectroscopy using quantum cascade lasers: mid-infrared refractometry and photothermal spectroscopy.

    Science.gov (United States)

    Pfeifer, Marcel; Ruf, Alexander; Fischer, Peer

    2013-11-04

    We record vibrational spectra with two indirect schemes that depend on the real part of the index of refraction: mid-infrared refractometry and photothermal spectroscopy. In the former, a quantum cascade laser (QCL) spot is imaged to determine the angles of total internal reflection, which yields the absorption line via a beam profile analysis. In the photothermal measurements, a tunable QCL excites vibrational resonances of a molecular monolayer, which heats the surrounding medium and changes its refractive index. This is observed with a probe laser in the visible. Sub-monolayer sensitivities are demonstrated.

  13. Quantitative monitoring of an activated sludge reactor using on-line UV-visible and near-infrared spectroscopy.

    Science.gov (United States)

    Sarraguça, Mafalda C; Paulo, Ana; Alves, Madalena M; Dias, Ana M A; Lopes, João A; Ferreira, Eugénio C

    2009-10-01

    The performance of an activated sludge reactor can be significantly enhanced through use of continuous and real-time process-state monitoring, which avoids the need to sample for off-line analysis and to use chemicals. Despite the complexity associated with wastewater treatment systems, spectroscopic methods coupled with chemometric tools have been shown to be powerful tools for bioprocess monitoring and control. Once implemented and optimized, these methods are fast, nondestructive, user friendly, and most importantly, they can be implemented in situ, permitting rapid inference of the process state at any moment. In this work, UV-visible and NIR spectroscopy were used to monitor an activated sludge reactor using in situ immersion probes connected to the respective analyzers by optical fibers. During the monitoring period, disturbances to the biological system were induced to test the ability of each spectroscopic method to detect the changes in the system. Calibration models based on partial least squares (PLS) regression were developed for three key process parameters, namely chemical oxygen demand (COD), nitrate concentration (N-NO(3)(-)), and total suspended solids (TSS). For NIR, the best results were achieved for TSS, with a relative error of 14.1% and a correlation coefficient of 0.91. The UV-visible technique gave similar results for the three parameters: an error of approximately 25% and correlation coefficients of approximately 0.82 for COD and TSS and 0.87 for N-NO(3)(-) . The results obtained demonstrate that both techniques are suitable for consideration as alternative methods for monitoring and controlling wastewater treatment processes, presenting clear advantages when compared with the reference methods for wastewater treatment process qualification.

  14. On-line near-infrared spectroscopy optimizing and monitoring biotransformation process of γ-aminobutyric acid

    Directory of Open Access Journals (Sweden)

    Guoyu Ding

    2016-06-01

    Full Text Available Near-infrared spectroscopy (NIRS with its fast and nondestructive advantages can be qualified for the real-time quantitative analysis. This paper demonstrates that NIRS combined with partial least squares (PLS regression can be used as a rapid analytical method to simultaneously quantify l-glutamic acid (l-Glu and γ-aminobutyric acid (GABA in a biotransformation process and to guide the optimization of production conditions when the merits of NIRS are combined with response surface methodology. The high performance liquid chromatography (HPLC reference analysis was performed by the o-phthaldialdehyde pre-column derivatization. NIRS measurements of two batches of 141 samples were firstly analyzed by PLS with several spectral pre-processing methods. Compared with those of the HPLC reference analysis, the resulting determination coefficients (R2, root mean square error of prediction (RMSEP and residual predictive deviation (RPD of the external validation for the l-Glu concentration were 99.5%, 1.62 g/L, and 11.3, respectively. For the GABA concentration, R2, RMSEP, and RPD were 99.8%, 4.00 g/L, and 16.4, respectively. This NIRS model was then used to optimize the biotransformation process through a Box-Behnken experimental design. Under the optimal conditions without pH adjustment, 200 g/L l-Glu could be catalyzed by 7148 U/L glutamate decarboxylase (GAD to GABA, reaching 99% conversion at the fifth hour. NIRS analysis provided timely information on the conversion from l-Glu to GABA. The results suggest that the NIRS model can not only be used for the routine profiling of enzymatic conversion, providing a simple and effective method of monitoring the biotransformation process of GABA, but also be considered to be an optimal tool to guide the optimization of production conditions.

  15. On-line near-infrared spectroscopy optimizing and monitoring biotransformation process ofγ-aminobutyric acid$

    Institute of Scientific and Technical Information of China (English)

    Guoyu Ding; Yuanyuan Hou; Jiamin Peng; Yunbing Shen; Min Jiang; Gang Bai

    2016-01-01

    Near-infrared spectroscopy (NIRS) with its fast and nondestructive advantages can be qualified for the real-time quantitative analysis. This paper demonstrates that NIRS combined with partial least squares (PLS) regression can be used as a rapid analytical method to simultaneously quantify L-glutamic acid (L-Glu) andγ-aminobutyric acid (GABA) in a biotransformation process and to guide the optimization of production conditions when the merits of NIRS are combined with response surface methodology. The high performance liquid chromatography (HPLC) reference analysis was performed by the o-phthaldialdehyde pre-column derivatization. NIRS measurements of two batches of 141 samples were firstly analyzed by PLS with several spectral pre-processing methods. Compared with those of the HPLC reference analysis, the resulting determination coefficients (R2), root mean square error of prediction (RMSEP) and residual predictive deviation (RPD) of the external validation for the L-Glu concentration were 99.5%, 1.62 g/L, and 11.3, respectively. For the GABA concentration, R2, RMSEP, and RPD were 99.8%, 4.00 g/L, and 16.4, re-spectively. This NIRS model was then used to optimize the biotransformation process through a Box-Behnken experimental design. Under the optimal conditions without pH adjustment, 200 g/L L-Glu could be catalyzed by 7148 U/L glutamate decarboxylase (GAD) to GABA, reaching 99%conversion at the fifth hour. NIRS analysis provided timely information on the conversion from L-Glu to GABA. The results suggest that the NIRS model can not only be used for the routine profiling of enzymatic conversion, providing a simple and effective method of monitoring the biotransformation process of GABA, but also be considered to be an optimal tool to guide the optimization of production conditions.

  16. In-Source Laser Spectroscopy with the Laser Ion Source and Trap: First Direct Study of the Ground-State Properties of ^{217,219}Po

    Directory of Open Access Journals (Sweden)

    D. A. Fink

    2015-02-01

    Full Text Available A Laser Ion Source and Trap (LIST for a thick-target, isotope-separation on-line facility has been implemented at CERN ISOLDE for the production of pure, laser-ionized, radioactive ion beams. It offers two modes of operation, either as an ion guide, which performs similarly to the standard ISOLDE resonance ionization laser ion source (RILIS, or as a more selective ion source, where surface-ionized ions from the hot ion-source cavity are repelled by an electrode, while laser ionization is done within a radio-frequency quadrupole ion guide. The first physics application of the LIST enables the suppression of francium contamination in ion beams of neutron-rich polonium isotopes at ISOLDE by more than 1000 with a reduction in laser-ionization efficiency of only 20. Resonance ionization spectroscopy is performed directly inside the LIST device, allowing the study of the hyperfine structure and isotope shift of ^{217}Po for the first time. Nuclear decay spectroscopy of ^{219}Po is performed for the first time, revealing its half-life, α-to-β-decay branching ratio, and α-particle energy. This experiment demonstrates the applicability of the LIST at radioactive ion-beam facilities for the production and study of pure beams of exotic isotopes.

  17. Study of laser-induced removal of co-deposits from tokamak plasma-facing components using ion diagnostics and optical spectroscopy

    Science.gov (United States)

    Wolowski, J.; Gasior, P.; Hoffman, J.; Kubkowska, M.; Rosinski, M.; Szymanski, Z.

    2010-10-01

    The paper presents studies of the application of ion diagnostics and optical spectroscopy for on-line measurement of the amount and characteristics of co-deposits from the laser-ablated surface of the plasma-facing components (e.g. graphite tiles). For removal of the co-deposit layer a repetitive Nd:YAG laser was used. Determination of the characteristics of ions emitted from the laser-illuminated targets was performed using ion collectors (on the basis of a time-of-flight method) and an optical spectrometer. The main ion stream parameters and spectral lines of deuterium and carbon or tungsten ions were measured depending on laser pulse parameters. The research proved that optical spectroscopy could be a convenient method for on-line observation of the co-deposited layer removal by means of laser ablation. In combination with the investigation of collected co-deposit dust, the performed study made it possible to state that laser-induced breakdown spectroscopy can be useful as a diagnostic method for the ablative co-deposited layer removal and the wall conditioning. The properties of modified surfaces of samples and collected dust (evaporated co-deposit) were determined using different measuring methods.

  18. Self-normalizing phase measurement in multimode terahertz spectroscopy based on photomixing of three lasers

    CERN Document Server

    Thirunavukkuarasu, K; Roggenbuck, A; Vidal, E; Schmitz, H; Hemberger, J; Grüninger, M

    2014-01-01

    Photomixing of two near-infrared lasers is well established for continuous-wave terahertz spectroscopy. Photomixing of three lasers allows us to measure at three terahertz frequencies simultaneously. Similar to Fourier spectroscopy, the spectral information is contained in an nterferogram, which is equivalent to the waveform in time-domain spectroscopy. We use one fixed terahertz frequency \

  19. Laser induced breakdown spectroscopy with picosecond pulse train

    Science.gov (United States)

    Lednev, Vasily N.; Pershin, Sergey M.; Sdvizhenskii, Pavel A.; Grishin, Mikhail Ya; Davydov, Mikhail A.; Stavertiy, Anton Ya; Tretyakov, Roman S.

    2017-02-01

    Picosecond pulse train and nanosecond pulse were compared for laser ablation and laser induced breakdown spectroscopy (LIBS) measurements. A detailed study revealed that the picosecond pulse train ablation improved the quality of laser craters (symmetric crater walls and the absence of large redeposited droplets), which was explained by a smaller heat affected zone and suppression of melt splash. Greater plasma dimensions and brighter plasma emission were observed by gated imaging for picosecond pulse train compared to nanosecond pulse ablation. Increased intensity of atomic and ionic lines in gated and time integrated spectra provided better signal-to-noise ratio for picosecond pulse train sampling. Higher temperature and electron density were detected during first microsecond for the plasma induced by the picosecond pulse train. Improved shot-to-shot reproducibility for atomic/ionic line intensity in the case of picosecond pulse train LIBS was explained by more effective atomization of target material in plasma and better quality of laser craters. Improved precision and limits of detections were determined for picosecond pulse train LIBS due to better reproducibility of laser sampling and increased signal-to-noise ratio.

  20. Laser Ultrasound Spectroscopy Scanning for 3D Printed Parts

    Energy Technology Data Exchange (ETDEWEB)

    Brennan, Guendalyn Kendra [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-08-04

    One of the challenges of additive manufacturing is quality control due to the possibility of unseen flaws in the final product. The current methods of inspection are lacking in detail, too slow for practical use, or unable to validate internal structure. This report examines the use of laser ultrasound spectroscopy in layer by layer scans of 3D printed parts as they are created. The result is fast and detailed quality control. An additional advantage of this method is the ability to cancel a print as soon as a defect is detected, therefore saving materials and time. This technique, though simple in concept, has been a challenge to implement. I discuss tweaking the 3D printer configuration, and finding the optimal settings for laser scanning small parts made of ABS plastic, as well as the limits of how small of a detail the laser can detect. These settings include the frequency of the ultrasonic transducer, the speed of the laser, and the distance from the laser to the part.

  1. Laser sources for precision spectroscopy on atomic strontium.

    Science.gov (United States)

    Poli, N; Ferrari, G; Prevedelli, M; Sorrentino, F; Drullinger, R E; Tino, G M

    2006-04-01

    We present a new laser setup designed for high-precision spectroscopy on laser cooled atomic strontium. The system, which is entirely based on semiconductor laser sources, delivers 200 mW at 461 nm for cooling and trapping atomic strontium from a thermal source, 4 mW at 497 nm for optical pumping from the metastable P23 state, 12 mW at 689 nm on linewidth less than 1 kHz for second-stage cooling of the atomic sample down to the recoil limit, 1.2 W at 922 nm for optical trapping close to the "magic wavelength" for the 0-1 intercombination line at 689 nm. The 689 nm laser was already employed to perform a frequency measurement of the 0-1 intercombination line with a relative accuracy of 2.3 x 10(-11), and the ensemble of laser sources allowed the loading in a conservative dipole trap of multi-isotopes strontium mixtures. The simple and compact setup developed represents one of the first steps towards the realization of a transportable optical standards referenced to atomic strontium.

  2. Two-Dimensional Fluorescence Spectroscopy for Measuring Uranium Isotopes in Femtosecond Laser Ablation

    Energy Technology Data Exchange (ETDEWEB)

    Phillips, Mark C.; Brumfield, Brian E.; Harilal, Sivanandan S.; Hartig, Kyle C.; Jovanovic, Igor

    2017-05-30

    We present the first two-dimensional fluorescence spectroscopy measurements of uranium isotopes in femtosecond laser ablation plasmas. A new method of signal normalization is presented to reduce noise in absorption-based measurements of laser ablation.

  3. Fluorescence cross-correlation spectroscopy using single wavelength laser

    Institute of Scientific and Technical Information of China (English)

    Chao XIE; Chaoqing DONG; Jicun REN

    2009-01-01

    In this paper, we first introduced the basic principle of fluorescence cross-correlation spectroscopy (FCCS) and then established an FCCS setup using a single wavelength laser. We systematically optimized the setup, and the detection volume reached about 0.7 fL. The home-built setup was successfully applied for the study of the binding reaction of human immunoglobulin G with goat antihuman immunoglobulin G. Using quantum dots (745 nm emission wavelength) and Rhodamine B (580 nm emission wavelength) as labeling probes and 532 nm laser beam as an excitation source, the cross-talk effect was almost completely suppressed. The molecule numbers in a highly focused volume, the concentration, and the diffusion time and hydrodynamic radii of the reaction products can be determined by FCCS system.

  4. LASER CORRELATION SPECTROSCOPY (LCS AND ITS CLINICAL PERSPECTIVES IN OPHTHALMOLOGY

    Directory of Open Access Journals (Sweden)

    Karganov Mikhail

    2015-12-01

    Full Text Available The method of laser correlation spectroscopy (LCS is based on the analysis of the spectrum of quasielastic light scatter during coherent monochromatic laser irradiation of micro-particles in biological fluids (blood serum, urine, oropharyngeal washout fluid, tear fluid etc.. Spectrum provides information on dynamic processes in the analyzed system: translation motion of scattering particles and their orientation and conformation dynamics. Special procedures of cluster analysis make it possible to find out to which linkage group a particular spectrum belongs. LCS allows evaluation of sub-fractional composition of biological fluids in a wide range of molecular sizes (from 1 to 10,000 nm, which determines principal novelty of this approach in ophthalmology.

  5. Spectrum standardization for laser-induced breakdown spectroscopy measurements

    CERN Document Server

    Wang, Zhe; West, Logan; Li, Zheng; Ni, Weidou

    2011-01-01

    This paper presents a spectra normalization method for laser-induced breakdown spectroscopy (LIBS) measurements by converting the recorded characteristic line intensity at varying conditions to the intensity under a standard condition with standard plasma temperature, degree of ionization, and total number density of the interested species to reduce the measurement uncertainty. The characteristic line intensities of the interested species are first converted to the intensity at a fixed temperature and standard degree of ionization but varying total number density for each laser pulse analysis. Under this state, if the influence of the variation of plasma morphology is neglected, the sum of multiple spectral line intensities for the measured element can be regarded proportional to the total number density of the specific element, and the fluctuation of the total number density, or the variation of ablation mass, was compensated for by the application of this relationship. In the experiments with 29 brass alloy...

  6. Tunable diode laser spectroscopy as a technique for combustion diagnostics

    Science.gov (United States)

    Bolshov, M. A.; Kuritsyn, Yu. A.; Romanovskii, Yu. V.

    2015-04-01

    Tunable diode laser absorption spectroscopy (TDLAS) has become a proven method of rapid gas diagnostics. In the present review an overview of the state of the art of TDL-based sensors and their applications for measurements of temperature, pressure, and species concentrations of gas components in harsh environments is given. In particular, the contemporary tunable diode laser systems, various methods of absorption detection (direct absorption measurements, wavelength modulation based phase sensitive detection), and relevant algorithms for data processing that improve accuracy and accelerate the diagnostics cycle are discussed in detail. The paper demonstrates how the recent developments of these methods and algorithms made it possible to extend the functionality of TDLAS in the tomographic imaging of combustion processes. Some prominent examples of applications of TDL-based sensors in a wide range of practical combustion aggregates, including scramjet engines and facilities, internal combustion engines, pulse detonation combustors, and coal gasifiers, are given in the final part of the review.

  7. Use of laser diodes in cavity ring-down spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Zare, R.N.; Paldus, B.A.; Ma, Y.; Xie, J. [Stanford Univ., CA (United States)

    1997-12-31

    We have demonstrated that cavity ring-down spectroscopy (CRDS), a highly sensitive absorption technique, is versatile enough to serve as a complete diagnostic for materials process control. In particular, we have used CRDS in the ultraviolet to determine the concentration profile of methyl radicals in a hot-filament diamond reactor; we have applied CRDS in the mid-infrared to detect 50 ppb of methane in a N{sub 2} environment; and, we have extended CRDS so that we can use continuous-wave diode laser sources. Using a laser diode at 810 nm, we were able to achieve a sensitivity of 2 x 10{sup -8} cm{sup -1}. Thus, CRDS can be used not only as an in situ diagnostic for investigating the chemistry of diamond film deposition, but it can also be used as a gas purity diagnostic for any chemical vapor deposition system.

  8. Analysis of fresco by laser induced breakdown spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Caneve, L., E-mail: luisa.caneve@enea.i [ENEA, CR Frascati, Via E. Fermi 45, 00044 Frascati (Italy); Diamanti, A. [Universita ' Tor Vergata' , Dipartimento di Scienze e Tecnologie Chimiche, via della Ricerca Scientifica 1, 00133 Roma (Italy); Grimaldi, F. [ENEA, CR Frascati, Via E. Fermi 45, 00044 Frascati (Italy); Palleschi, G. [Universita ' Tor Vergata' , Dipartimento di Scienze e Tecnologie Chimiche, via della Ricerca Scientifica 1, 00133 Roma (Italy); Spizzichino, V. [ENEA, CR Frascati, Via E. Fermi 45, 00044 Frascati (Italy); Valentini, F. [Universita ' Tor Vergata' , Dipartimento di Scienze e Tecnologie Chimiche, via della Ricerca Scientifica 1, 00133 Roma (Italy)

    2010-08-15

    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.

  9. Analysis of fresco by laser induced breakdown spectroscopy

    Science.gov (United States)

    Caneve, L.; Diamanti, A.; Grimaldi, F.; Palleschi, G.; Spizzichino, V.; Valentini, F.

    2010-08-01

    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.

  10. Standoff detection of gases using infrared laser spectroscopy

    Science.gov (United States)

    Jaworski, Piotr; Stachowiak, Dorota; Nikodem, Michał

    2016-04-01

    In this work we present a laser-based system for standoff/remote, sensitive detection of gases based on a tunable diode laser source and Wavelength Modulation Spectroscopy method (WMS). System performance was experimentally characterized. The constructed device has proven its capacity of efficient detection of methane in air at the single ppm levels and distances from 10 to 50 m (distance to a scattering object). The minimum detection limit of the system was estimated at the level of 10 ppm-m for the standoff arrangement and the measurement path of approximately 20 m (round trip). Potential application of the device to hydrogen sulfide detection and current limitations in this area are discussed.

  11. Quantitative analysis of gallstones using laser-induced breakdown spectroscopy.

    Science.gov (United States)

    Singh, Vivek K; Singh, Vinita; Rai, Awadhesh K; Thakur, Surya N; Rai, Pradeep K; Singh, Jagdish P

    2008-11-01

    The utility of laser-induced breakdown spectroscopy (LIBS) for categorizing different types of gallbladder stone has been demonstrated by analyzing their major and minor constituents. LIBS spectra of three types of gallstone have been recorded in the 200-900 nm spectral region. Calcium is found to be the major element in all types of gallbladder stone. The spectrophotometric method has been used to classify the stones. A calibration-free LIBS method has been used for the quantitative analysis of metal elements, and the results have been compared with those obtained from inductively coupled plasma atomic emission spectroscopy (ICP-AES) measurements. The single-shot LIBS spectra from different points on the cross section (in steps of 0.5 mm from one end to the other) of gallstones have also been recorded to study the variation of constituents from the center to the surface. The presence of different metal elements and their possible role in gallstone formation is discussed.

  12. Laser-induced breakdown spectroscopy of tantalum plasma

    Energy Technology Data Exchange (ETDEWEB)

    Khan, Sidra; Bashir, Shazia; Hayat, Asma; Khaleeq-ur-Rahman, M.; Faizan–ul-Haq [Centre for Advanced Studies in Physics, GC University, Lahore (Pakistan)

    2013-07-15

    Laser Induced Breakdown spectroscopy (LIBS) of Tantalum (Ta) plasma has been investigated. For this purpose Q-switched Nd: YAG laser pulses (λ∼ 1064 nm, τ∼ 10 ns) of maximum pulse energy of 100 mJ have been employed as an ablation source. Ta targets were exposed under the ambient environment of various gases of Ar, mixture (CO{sub 2}: N{sub 2}: He), O{sub 2}, N{sub 2}, and He under various filling pressure. The emission spectrum of Ta is observed by using LIBS spectrometer. The emission intensity, excitation temperature, and electron number density of Ta plasma have been evaluated as a function of pressure for various gases. Our experimental results reveal that the optical emission intensity, the electron temperature and density are strongly dependent upon the nature and pressure of ambient environment. The SEM analysis of the ablated Ta target has also been carried out to explore the effect of ambient environment on the laser induced grown structures. The growth of grain like structures in case of molecular gases and cone-formation in case of inert gases is observed. The evaluated plasma parameters by LIBS analysis such as electron temperature and the electron density are well correlated with the surface modification of laser irradiated Ta revealed by SEM analysis.

  13. Measurement of Irradiated Pyroprocessing Samples via Laser Induced Breakdown Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Phongikaroon, Supathorn [Virginia Commonwealth Univ., Richmond, VA (United States)

    2016-10-31

    The primary objective of this research is to develop an applied technology and provide an assessment to remotely measure and analyze the real time or near real time concentrations of used nuclear fuel (UNF) dissolute in electrorefiners. Here, Laser-Induced Breakdown Spectroscopy (LIBS), in UNF pyroprocessing facilities will be investigated. LIBS is an elemental analysis method, which is based on the emission from plasma generated by focusing a laser beam into the medium. This technology has been reported to be applicable in the media of solids, liquids (includes molten metals), and gases for detecting elements of special nuclear materials. The advantages of applying the technology for pyroprocessing facilities are: (i) Rapid real-time elemental analysis|one measurement/laser pulse, or average spectra from multiple laser pulses for greater accuracy in < 2 minutes; (ii) Direct detection of elements and impurities in the system with low detection limits|element specific, ranging from 2-1000 ppm for most elements; and (iii) Near non-destructive elemental analysis method (about 1 g material). One important challenge to overcome is achieving high-resolution spectral analysis to quantitatively analyze all important fission products and actinides. Another important challenge is related to accessibility of molten salt, which is heated in a heavily insulated, remotely operated furnace in a high radiation environment with an argon atmosphere.

  14. Dust Removal on Mars Using Laser-Induced Breakdown Spectroscopy

    Science.gov (United States)

    Graff, T. G.; Morris, R. V.; Clegg, S. M.; Wiens, R. C.; Anderson, R. B.

    2011-01-01

    Dust coatings on the surface of Mars complicate and, if sufficiently thick, mask the spectral characteristics and compositional determination of underlying material from in situ and remote sensing instrumentation. The Laser-Induced Breakdown Spectroscopy (LIBS) portion of the Chemistry & Camera (ChemCam) instrument, aboard the Mars Science Laboratory (MSL) rover, will be the first active remote sensing technique deployed on Mars able to remove dust. ChemCam utilizes a 5 ns pulsed 1067 nm high-powered laser focused to less than 400 m diameter on targets at distances up to 7 m [1,2]. With multiple laser pulses, dust and weathering coatings can be remotely analyzed and potentially removed using this technique [2,3]. A typical LIBS measurement during MSL surface operations is planned to consist of 50 laser pulses at 14 mJ, with the first 5 to 10 pulses used to analyze as well as remove any surface coating. Additionally, ChemCam's Remote Micro-Imager (RMI) is capable of resolving 200 m details at a distance of 2 m, or 1 mm at 10 m [1,4]. In this study, we report on initial laboratory experiments conducted to characterize the removal of dust coatings using similar LIBS parameters as ChemCam under Mars-like conditions. These experiments serve to better understand the removal of surface dust using LIBS and to facilitate the analysis of ChemCam LIBS spectral data and RMI images.

  15. Spatial confinement in laser-induced breakdown spectroscopy

    Science.gov (United States)

    Li, Xingwen; Yang, Zefeng; Wu, Jian; Wei, Wenfu; Qiu, Yan; Jia, Shenli; Qiu, Aici

    2017-01-01

    The spatial confinement of plasma produced by a nanosecond laser is investigated using time resolved spectroscopy, fast imaging, interferometry, and numerical computation. The dynamics of the plasma, depending on shock waves, laser power, and wall distances, are studied. Experimental results confirm that the plasma is constricted by the reflected shock associated with a temperature and density gradient. The peak laser power determines the initial plasma parameters which affect the spectral intensities and the velocity of the reflective shock waves. The wall distance determines the reflection time of the shocks, which in turn influences the time delay of the collision between the two reflective shocks. The numerical results reveal a fast propagation process surrounding the reflective shocks, which indicates that the velocity of the reflective shock wave is influenced by the density of the plasma. The maximum enhancement factor ~5.2 is realized at a delay time of 11.7 µs under a pulse laser energy of 180 mJ and a wall distance of 9 mm.

  16. Biomedical and environmental applications of laser-induced breakdown spectroscopy

    Indian Academy of Sciences (India)

    V K Unnikrishnan; K S Choudhari; Suresh D Kulkarni; Rajesh Nayak; V B Kartha; C Santhosh; B M Suri

    2014-02-01

    Laser-induced breakdown spectroscopy (LIBS) is an emerging analytical technique with numerous advantages such as rapidity, multi-elemental analysis, minimal sample preparation, minimal destruction, low cost and versatility of being applied to a wide range of materials. In this paper, we report the preliminary observations we obtained using LIBS for clinical and environmental samples. Elemental analysis has been done qualitatively in human teeth samples which show encouraging results. It has also been demonstrated in this paper that LIBS can be very well utilized in field applications such as plastic waste sorting and recycling.

  17. Controlled calibration method for laser induced breakdown spectroscopy

    Institute of Scientific and Technical Information of China (English)

    Li Wang; Chijian Zhang; Yuan Feng

    2008-01-01

    Laser induced breakdown spectroscopy (LIBS) is a potential technique for rapid analysis of samples present in solids, gases and liquids. In the last two decades it was an object of extensive studies. Controlled calibration method used to analysis the LIBS spectra is investigated. Compared with the inner calibration and calibration-free (CF) methods, this new method overcomes "matrix effect", and demonstrates a better ability to cope with the spectra. It is used to analyze natural soil, and errors of the concentration are decreased about 5%. The result shows that the new method is feasible and accurate.

  18. Analysis of dissolved C2H2 in transformer oils using laser Raman spectroscopy.

    Science.gov (United States)

    Somekawa, Toshihiro; Kasaoka, Makoto; Kawachi, Fumio; Nagano, Yoshitomo; Fujita, Masayuki; Izawa, Yasukazu

    2013-04-01

    We have developed a laser Raman spectroscopy technique for assessing the working conditions of transformers by measuring dissolved C2H2 gas concentrations present in transformer oils. A frequency doubled Q-switched Nd:YAG laser (532 nm) was used as a laser source, and Raman signals at ~1972 cm(-1) originating from C2H2 gas dissolved in oil were detected. The results show that laser Raman spectroscopy is a useful alternative method for detecting transformer faults.

  19. ARTICLES: Influence Factors on Particle Growth for On-line Aerosol Matrix-assisted Laser Desorption/Ionization Time-of-flight Mass Spectrometry

    Science.gov (United States)

    Xia, Wei-wei; Ti, Ru-fang; Zhang, Zi-Iiang; Zheng, Hai-yang; Fang, Li

    2010-06-01

    An evaporation/condensation flow cell was developed and interfaced with the matrix-assisted laser desorption/ionization (MALDI) time-of-flight mass spectrometer for on-line bioaerosol detection and characterization, which allows matrix addition by condensation onto the laboratory-generated bioaerosol particles. The final coated particle exiting from the condenser is then introduced into the aerodynamic particle sizer spectrometer or home-built aerosol laser time-of-flight mass spectrometer, and its aerodynamic size directly effects on the matrix-to-analyte molar ratio, which is very important for MALDI technique. In order to observe the protonated analyte molecular ion, and then determine the classification of biological aerosols, the matrix-to-analyte molar ratio must be appropriate. Four experimental parameters, including the temperature of the heated reservoir, the initial particle size, its number concentration, and the matrix material, were tested experimentally to analyze their influences on the final particle size. This technique represents an on-line system of detection that has the potential to provide rapid and reliable identification of airborne biological aerosols.

  20. Application of matrix-assisted laser desorption/ionization to on-line aerosol time-of-flight mass spectrometry

    NARCIS (Netherlands)

    Stowers, M.A.; Wuijckhuijse, A.L. van; Marijnissen, J.C.M.; Scarlett, B.; Baar, B.L.M. van; Kientz, Ch.E.

    2000-01-01

    Matrix-assisted laser desorption/ionization (MALDI) mass spectra were obtained from single biological aerosol particles using an aerosol time-of- flight mass spectrometer (ATOFMS). The inlet to the ATOFMS was coupled with an evaporation/condensation flow cell that allowed the aerosol to be coated wi

  1. 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.

  2. Investigation of Diode Pumped Alkali Laser Atmospheric Transmission Using Tunable Diode Laser Absorption Spectroscopy

    Science.gov (United States)

    2012-09-01

    House Appropriations hearing on May 20th, 2010 where Robert Gates, then U.S. Secretary of Defense, said the following in answer to a question from Rep...Henry, B. P. Wert, T. Gilpin , and J. R. Drummond. “Tunable diode laser absorption spectrometer for ground-based measurements of formaldehyde”. Journal...spectroscopy (TDLAS) at 1.37 µm”. Applied Physics B: Lasers and Optics, 92(3):393–401, 2008. 43. Kormann, Robert , Horst Fischer, and Frank G. Wienhold

  3. Laser ablation of powdered samples and analysis by means of laser-induced breakdown spectroscopy

    Science.gov (United States)

    Ctvrtnickova, T.; Cabalin, L.; Laserna, J.; Kanicky, V.; Nicolas, G.

    2009-03-01

    The presented work proves the capacities of laser-induced breakdown spectroscopy (LIBS) as a fast, universal, and versatile technique for analysis of complex materials as ceramics. This paper reports on the analysis of ceramic raw materials (brick clays and kaolin) submitted to laser ablation in the form of pressed pellets. Spectrographic study was provided by standard single-pulse LIBS technique and orthogonal reheating double-pulse LIBS. It was found that both methods are comparable in terms of analytical performance, if adequate experimental parameters and signal detection systems are used.

  4. 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.

  5. Ring-Down Spectroscopy for Characterizing a CW Raman Laser

    Science.gov (United States)

    Matsko, Andrey; Savchenkov, Anatoliy; Maleki, Lute

    2007-01-01

    .A relatively simple technique for characterizing an all-resonant intracavity continuous-wave (CW) solid-state Raman laser involves the use of ring-down spectroscopy. As used here, characterizing signifies determining such parameters as threshold pump power, Raman gain, conversion efficiency, and quality factors (Q values) of the pump and Stokes cavity modes. Heretofore, in order to characterize resonant-cavity-based Raman lasers, it has usually been necessary to manipulate the frequencies and power levels of pump lasers and, in each case, to take several sets of measurements. In cases involving ultra-high-Q resonators, it also has been desirable to lock pump lasers to resonator modes to ensure the quality of measurement data. Simpler techniques could be useful. In the present ring-down spectroscopic technique, one infers the parameters of interest from the decay of the laser out of its steady state. This technique does not require changing the power or frequency of the pump laser or locking the pump laser to the resonator mode. The technique is based on a theoretical analysis of what happens when the pump laser is abruptly switched off after the Raman generation reaches the steady state. The analysis starts with differential equations for the evolution of the amplitudes of the pump and Stokes electric fields, leading to solutions for the power levels of the pump and Stokes fields as functions of time and of the aforementioned parameters. Among other things, these solutions show how the ring-down time depends, to some extent, on the electromagnetic energy accumulated in the cavity. The solutions are readily converted to relatively simple equations for the parameters as functions of quantities that can be determined from measurements of the time-dependent power levels. For example, the steady-state intracavity conversion efficiency is given by G1/G2 1 and the threshold power is given by Pin(G2/G1)2, where Pin is the steady-state input pump power immediately prior to

  6. Discrimination of forensic trace evidence using laser induced breakdown spectroscopy

    Science.gov (United States)

    Bridge, Candice Mae

    Elemental analysis in forensic laboratories can be tedious and many trace evidence items are not analyzed to determine their elemental composition. Presently, scanning electron microscopy-energy dispersive x-ray spectroscopy (SEM-EDS) is the primary analytical tool for determining the elemental composition of trace evidence items. However, due to the time it takes to obtain the required vacuum and the limited number of samples that can be analyzed at any one time, SEM-EDS can be impractical for a high volume of evidence items. An alternative instrument that can be used for this type of analysis is laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). While LA-ICP-MS is a very precise and quantitative analytical method that determines elemental composition based on isotopic mass measurements; however, the instrumentation is relatively expensive and therefore is budgetarily prohibitive for many forensic laboratories. It is the purpose of this research to evaluate an inexpensive instrument that can potentially provide rapid elemental analysis for many forensic laboratories. Laser induced breakdown spectroscopy (LIBS) is an analytical method that meets these requirements and offers information about the elemental composition based on ionic, atomic and diatomic molecular emissions.

  7. PREFACE: 21st International Conference on Laser Spectroscopy - ICOLS 2013

    Science.gov (United States)

    Budker, Dmitry; Häffner, Hartmut; Müller, Holger

    2013-12-01

    The 21st International Conference on Laser Spectroscopy (ICOLS) took place at Berkeley, California on 9-14 June 2013. Following the tradition of previous meetings in this series, the conference featured about thirty invited talks broadly covering this burgeoning field of science that refuses to show any sign of saturation after more than half a century of continuous boom. In addition to the invited talks, there were two informative poster sessions, where the more than 300 ICOLS participants had an opportunity to exchange the latest scientific news and ideas while enjoying the gorgeous view of the San Francisco Bay from the vista of the Claremont Hotel, the meeting's venue. The heights of the cultural program of the meeting were excursions to several of the Bay Area gems (including the Lick observatory), as well as the conference banquet where the participants were treated to addresses by an inventor of the laser Professor Charles H Townes, a nonlinear optics pioneer Professor Erwin L Hahn, and one of the previous ICOLS chairs Professor Y R Shen. While the field of Laser Spectroscopy and the series of the bi-annual ICOLS meetings are as 'healthy' as one could imagine, the same cannot be said about the concept of published conference proceedings. With new ways to publish scientific articles and preprints, submitting papers to conference proceedings seems to be rapidly losing popularity. For this meeting, the great interest in attendance and opportunities to present is sharply contrasted with a somewhat sluggish response to the call for submission of the proceedings papers. The present collection represents a dozen or so contributions from the 'hero' invited speakers, to whom we are deeply grateful for submitting their work. We hope that this selection will faithfully convey to the readers the excitement of modern laser spectroscopy. In addition to these papers, we draw the reader's attention to the audio recordings and selected viewgraphs from the invited talks, and

  8. Multivariate Curve Resolution Combined with On-line Infrared Spectroscopy for Researching the Synthesis Mechanism of 3,4-Bis(4'-aminofurazano-3')furoxan

    Institute of Scientific and Technical Information of China (English)

    WU Nan; SUN Kun-lun; LIU Yu; YANG Xiao-feng; LI Hua

    2013-01-01

    3,4-Bis(4'-aminofurazano-3')furoxan(DATF),one of a new generation of high energy density materials,shows lots of interesting properties such as lower sensitivity,excellent thermal stability and superior detonation performance in chemistry and physics.In this paper,on-line infrared(IR) spectroscopy was used to monitor the synthesis process of DATF.The concentration profiles and IR spectra of the components were determined by analyzing the IR data via principal component analysis(PCA),evolving factor analysis(EFA) and multivariate curve resolution-alternating least squares(MCR-ALS).The geometric configurations of reactant,intermediates and product were optimized with the density functional theory(DFT) at B3LYP/6-3 1+G(d,p) level.Their vibrational frequencies and IR spectra were obtained on the basis of vibrational analysis.The result obtained by the chemometric resolution methods agreed well with that obtained by quantum chemical calculation method,which demonstrated the reliability of the proposed chemometric resolution methods.The unstable intermediate 3-amino-4-oxycyanofurazan(AOF) was confirmed via comparing the IR spectra resloved by chemometric resolution methods with those calculated by B3LYP/6-31+G(d,p) and analyzed by MCR-ALS.Finally,the possible synthesis mechanism of DATF was deduced by analyzing the above 1R spectra.

  9. Enhancing the analytical performance of laser-induced breakdown spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Cremers, D.A.; Chinni, R.C.; Pichahchy, A.E.; Thornquist, H.K.

    1998-12-31

    This is the final report of a one-year, Laboratory Directed Research and Development (LDRD) project at Los Alamos National Laboratory (LANL). The objective of this work is to enhance the analytical capabilities of laser-induced breakdown spectroscopy (LIBS). LIBS is a method of elemental analysis in which powerful laser pulses are focused on a sample to form a microplasma. LIBS is perhaps the most versatile elemental analysis method, applicable to a variety of different real-world analysis problems. Therefore, it is important to enhance the capabilities of the method as much as possible. Accomplishments include: (1) demonstration of signal enhancements of 5--30 times from soils and metals using a double pulse method; (2) development of a model of the observed enhancement obtained using double pulses; (3) demonstration that the analytical performance achievable using low laser-pulse energies (10 and 25 mJ) can match that achievable using an energy of 100 mJ; and (4) demonstration that time-gated detection is not necessary with LIBS.

  10. Applying Quantum Cascade Laser Spectroscopy in Plasma Diagnostics

    Directory of Open Access Journals (Sweden)

    Jürgen Röpcke

    2016-07-01

    Full Text Available The considerably higher power and wider frequency coverage available from quantum cascade lasers (QCLs in comparison to lead salt diode lasers has led to substantial advances when QCLs are used in pure and applied infrared spectroscopy. Furthermore, they can be used in both pulsed and continuous wave (cw operation, opening up new possibilities in quantitative time resolved applications in plasmas both in the laboratory and in industry as shown in this article. However, in order to determine absolute concentrations accurately using pulsed QCLs, careful attention has to be paid to features like power saturation phenomena. Hence, we begin with a discussion of the non-linear effects which must be considered when using short or long pulse mode operation. More recently, cw QCLs have been introduced which have the advantage of higher power, better spectral resolution and lower fluctuations in light intensity compared to pulsed devices. They have proved particularly useful in sensing applications in plasmas when very low concentrations have to be monitored. Finally, the use of cw external cavity QCLs (EC-QCLs for multi species detection is described, using a diagnostics study of a methane/nitrogen plasma as an example. The wide frequency coverage of this type of QCL laser, which is significantly broader than from a distributed feedback QCL (DFB-QCL, is a substantial advantage for multi species detection. Therefore, cw EC-QCLs are state of the art devices and have enormous potential for future plasma diagnostic studies.

  11. Single-shot spectroscopy of broadband Yb fiber laser

    Science.gov (United States)

    Suzuki, Masayuki; Yoneya, Shin; Kuroda, Hiroto

    2017-02-01

    We have experimentally reported on a real-time single-shot spectroscopy of a broadband Yb-doped fiber (YDF) laser which based on a nonlinear polarization evolution by using a time-stretched dispersive Fourier transformation technique. We have measured an 8000 consecutive single-shot spectra of mode locking and noise-like pulse (NLP), because our developed broadband YDF oscillator can individually operate the mode locking and NLP by controlling a pump LD power and angle of waveplates. A shot-to-shot spectral fluctuation was observed in NLP. For the investigation of pulse formation dynamics, we have measured the spectral evolution in an initial fluctuations of mode locked broadband YDF laser at an intracavity dispersion of 1500 and 6200 fs2 for the first time. In both case, a build-up time between cw and steady-state mode locking was estimated to be 50 us, the dynamics of spectral evolution between cw and mode locking, however, was completely different. A shot-to-shot strong spectral fluctuation, as can be seen in NLP spectra, was observed in the initial timescale of 20 us at the intracavity dispersion of 1500 fs2. These new findings would impact on understanding the birth of the broadband spectral formation in fiber laser oscillator.

  12. A compact field-portable double-pulse laser system to enhance laser induced breakdown spectroscopy

    Science.gov (United States)

    Li, Shuo; Liu, Lei; Yan, Aidong; Huang, Sheng; Huang, Xi; Chen, Rongzhang; Lu, Yongfeng; Chen, Kevin

    2017-02-01

    This paper reports the development of a compact double-pulse laser system to enhance laser induced breakdown spectroscopy (LIBS) for field applications. Pumped by high-power vertical-surface emitting lasers, the laser system that produces 16 ns pulse at 12 mJ/pulse with total weight less than 10 kg is developed. The inter-pulse delay can be adjusted from 0 μ s with 0.5 μ s increment. Several LIBS experiments were carried out on NIST standard aluminum alloy samples. Comparing with the single-pulse LIBS, up to 9 times enhancement in atomic emission line was achieved with continuum background emission reduced by 70%. This has led to up to 10 times improvement in the limit of detection. Signal stability was also improved by 128% indicating that a more robust and accurate LIBS measurement can be achieved using a compact double-pulse laser system. This paper presents a viable and field deployable laser tool to dramatically improve the sensitivity and applicability of LIBS for a wide array of applications.

  13. Laser mass spectrometry as on-line sensor for industrial process analysis: process control of coffee roasting.

    Science.gov (United States)

    Dorfner, Ralph; Ferge, Thomas; Yeretzian, Chahan; Kettrup, Antonius; Zimmermann, Ralf

    2004-03-01

    The objective of the project is to develop on-line, real-time, and noninvasive process control tools of coffee roasting that help deliver a consistent and high-quality coffee aroma. The coffee roasting process was analyzed by direct injection of the roaster gas into a time-of-flight mass spectrometer and ionized either by resonance enhanced multiphoton ionization (REMPI) at 266 and 248 nm or vacuum ultraviolet single-photon ionization (VUV-SPI) at 118 nm. The VUV ionization scheme allows detecting mainly the most volatile and abundant compounds of molecular mass below 100 m/z, while REMPI ionizes mainly aromatic compounds of molecular mass larger than 100 m/z. Combining the compounds ionized by resonant and single-photon ionization, approximately 30 volatile organic compounds are monitored in real time. Time-intensity profiles of 10 important volatile coffee compounds were discussed in connection with their formation chemistry during roasting. Applying multivariate statistics (principle component analysis) on time-intensity traces of nine volatile coffee compounds, the roasting degree could be traced as a consistent path in the score plot of the two most significant principle components (including 68% of the total variance), for a range of roasting temperatures (200-250 degrees C).

  14. Double-pulse laser ablation coupled to laser-induced breakdown spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Glaus, Reto, E-mail: reglaus@ufl.edu; Hahn, David W.

    2014-08-01

    Laser ablation coupled to laser-induced breakdown spectroscopy (LA-LIBS) is an analytical method, which minimizes sample matrix effects typically found in quantitative LIBS-based direct solid analyses. This paper reports the application of double-pulse laser ablation (DP-LA) to improve the analyte response and the achievable precisions of LA-LIBS. Two coaxial laser beams were applied at the ablation site and the analytical signals were then collected from a second free-standing LIBS plasma downstream of the ablation site. Signal improvements of up to one order of magnitude were observed compared to single-pulse LA-LIBS. The effect of the interpulse delay on the observed signal-to-noise ratios was studied and the quantification capabilities of the optimized DP-LA-LIBS setup were investigated for manganese and iron in a broad range of different alloy types. A linear response was observed for manganese across the different matrices, allowing for nonmatrix-matched calibrations. Matrix effects were observed when analyzing aluminum samples, which, however, could be compensated for by applying iron as internal standard. Size distributions of the ablated material and electron density measurements provide additional insight into the double-pulse process, with additional future work suggested. - Highlights: • Double-pulse laser ablation was coupled to laser-induced breakdown spectroscopy. • Nonmatrix-matched calibration of manganese in various alloys was performed. • Improved sensitivities and precisions compared to single-pulse LA were demonstrated. • Remaining matrix effects and internal standardization are discussed.

  15. Sampling considerations when analyzing micrometric-sized particles in a liquid jet using laser induced breakdown spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Faye, C.B.; Amodeo, T.; Fréjafon, E. [Institut National de l' Environnement Industriel et des Risques (INERIS/DRC/CARA/NOVA), Parc Technologique Alata, BP 2, 60550 Verneuil-En-Halatte (France); Delepine-Gilon, N. [Institut des Sciences Analytiques, 5 rue de la Doua, 69100 Villeurbanne (France); Dutouquet, C., E-mail: christophe.dutouquet@ineris.fr [Institut National de l' Environnement Industriel et des Risques (INERIS/DRC/CARA/NOVA), Parc Technologique Alata, BP 2, 60550 Verneuil-En-Halatte (France)

    2014-01-01

    Pollution of water is a matter of concern all over the earth. Particles are known to play an important role in the transportation of pollutants in this medium. In addition, the emergence of new materials such as NOAA (Nano-Objects, their Aggregates and their Agglomerates) emphasizes the need to develop adapted instruments for their detection. Surveillance of pollutants in particulate form in waste waters in industries involved in nanoparticle manufacturing and processing is a telling example of possible applications of such instrumental development. The LIBS (laser-induced breakdown spectroscopy) technique coupled with the liquid jet as sampling mode for suspensions was deemed as a potential candidate for on-line and real time monitoring. With the final aim in view to obtain the best detection limits, the interaction of nanosecond laser pulses with the liquid jet was examined. The evolution of the volume sampled by laser pulses was estimated as a function of the laser energy applying conditional analysis when analyzing a suspension of micrometric-sized particles of borosilicate glass. An estimation of the sampled depth was made. Along with the estimation of the sampled volume, the evolution of the SNR (signal to noise ratio) as a function of the laser energy was investigated as well. Eventually, the laser energy and the corresponding fluence optimizing both the sampling volume and the SNR were determined. The obtained results highlight intrinsic limitations of the liquid jet sampling mode when using 532 nm nanosecond laser pulses with suspensions. - Highlights: • Micrometric-sized particles in suspensions are analyzed using LIBS and a liquid jet. • The evolution of the sampling volume is estimated as a function of laser energy. • The sampling volume happens to saturate beyond a certain laser fluence. • Its value was found much lower than the beam diameter times the jet thickness. • Particles proved not to be entirely vaporized.

  16. In situ UV–Vis diffuse reflectance spectroscopyon line activity measurements of supported chromium oxide catalysts: relating isobutane dehydrogenation activity with Cr-speciation via experimental design

    NARCIS (Netherlands)

    Weckhuysen, B.M.; Verberckmoes, A.A.; Debaere, J.; Ooms, K.; Langhans, I.; Schoonheydt, R.A.

    2000-01-01

    The dehydrogenation of isobutane over supported chromium oxide catalysts was studied by a combination of in situ UV–Vis diffuse reflectance spectroscopy and on line GC analysis. A well-defined set of experiments, based on an experimental design, was carried out to develop mathematical models, which

  17. [Multi-harmonic analysis of quasi-continuous-wave laser modulation absorption spectroscopy].

    Science.gov (United States)

    Qi, Ru-bin; Du, Zhen-hui; Meng, Fan-li; Li, Jin-yi; Gao, Dong-yu; Xu, Xiao-bin; Chen, Wen-liang; Xu, Ke-xin

    2012-03-01

    Numerous harmonic components such as multiple frequency, sum frequency and difference frequency of multiple modulation signals were found in quasi-continuous-wave (QCW) diode laser modulation absorption spectroscopy. Then, the authors analyzed these harmonic components' existence in terms of non-linear interactions of laser and gas absorption line. And the signals' characteristics were studied experimentally. The results shows that there are some sum frequency and difference frequency components that have larger amplitudes compared to the second harmonic wavelength modulation spectroscopy signal (2f-WMS) commonly used in tunable diode laser spectroscopy (TDLAS), and it may improve the detection sensitivity of QCW modulation spectroscopy.

  18. Measurement of nuclear moments and radii by collinear laser spectroscopy

    CERN Multimedia

    Geithner, W R; Lievens, P; Kotrotsios, G; Silverans, R; Kappertz, S

    2002-01-01

    %IS304 %title\\\\ \\\\Collinear laser spectroscopy on a fast beam has proven to be a widely applicable and very efficient tool for measurements of changes in mean square nuclear charge radii, nuclear spins, magnetic dipole and electric quadrupole moments. Recent developments of extremely sensitive non-optical detection schemes enabled for some elements the extension of the measurements towards the very short-lived isotopes in the far wings of the ISOLDE production curves. The gain in sensitivity opens up new perspectives, particularly for measurements on lighter nuclei whose ground-state properties can be interpreted by large scale microscopic calculations instead of the more phenomenologic models used for heavier nuclei.\\\\ \\\\ For the sequence of argon isotopes $^{32-40}$Ar and $^{46}$Ar isotope shifts and nuclear moments were measured by optical pumping followed by state selective collisional ionization and detection of the $\\beta$-decay. Similarly, the low-background $\\alpha$-detection was used to extend earlie...

  19. Parity violation tests in chiral molecules by laser spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Chardonnet, Ch.; Daussy, Ch.; Marrel, T.; Amy-Klein, A.; Nguyen, C.T.; Borde, Ch.J. [Paris-13 Univ., 93 - Villetaneuse (France). Lab. de Physique des Lasers

    1999-07-01

    A laser nonlinear spectroscopy experiment has been designed and implemented to test the conjecture that enantiomers of chiral molecules may have different spectra because of the parity violation associated with neutral currents in the weak interaction between electrons and nuclei. We review the theoretical reasons that lead to this prediction and we outline the method currently used to calculate energy and frequency differences between mirror image molecules. Preliminary experimental tests have been conducted on hyperfine components of vibration-rotation transitions of CHFClBr in the 9.3 {mu}m spectral range. The frequencies of saturation resonances of separated enantiomers have been compared and found identical within 13 Hz ({delta}{nu}/{nu} <4.10{sup -13}). (authors)

  20. Laser-induced breakdown spectroscopy fundamentals and applications

    CERN Document Server

    Noll, Reinhard

    2012-01-01

    This book is a comprehensive source of the fundamentals, process parameters, instrumental components and applications of laser-induced breakdown spectroscopy (LIBS). The effect of multiple pulses on material ablation, plasma dynamics and plasma emission is presented. A heuristic plasma modeling allows to simulate complex experimental plasma spectra. These methods and findings form the basis for a variety of applications to perform quantitative multi-element analysis with LIBS. These application potentials of LIBS have really boosted in the last years ranging from bulk analysis of metallic alloys and non-conducting materials, via spatially resolved analysis and depth profiling covering measuring objects in all physical states: gaseous, liquid and solid. Dedicated chapters present LIBS investigations for these tasks with special emphasis on the methodical and instrumental concepts as well as the optimization strategies for a quantitative analysis. Requirements, concepts, design and characteristic features of LI...

  1. Analytical study of seashell using laser-induced breakdown spectroscopy

    Science.gov (United States)

    Ying, LI; Yanhong, GU; Ying, Zhang; Yuandong, LI; Yuan, LU

    2017-02-01

    Seashell has been applied as an indicator for ocean research and element analysis of the seashell is used to track biological or environmental evolution. In this work, laser-induced breakdown spectroscopy (LIBS) was applied for elementary analysis of an ezo scallop-shell, and a graphite enrichment method was used as the assistance. It was found that LIBS signal intensity of Ca fluctuated less than 5%, in spite of the sampling positions, and Sr/Ca was related to the shell growth. A similar variation was also found when using a direct LIBS analysis on the shell surface, and it might be more practicable to track shell growth by investigating Sr/Ca ratio with Sr ionic line at 421.6 nm. The obtained results prove that calcium (Ca) is qualified as an internal reference for shell analysis, and LIBS is a potential analytical method for seashell study.

  2. Characterization of a Continuous Wave Laser for Resonance Ionization Mass Spectroscopy Analysis in Nuclear Forensics

    Science.gov (United States)

    2015-06-01

    OF A CONTINUOUS WAVE LASER FOR RESONANCE IONIZATION MASS SPECTROSCOPY ANALYSIS IN NUCLEAR FORENSICS by Sunny G. Lau June 2015 Thesis...IONIZATION MASS SPECTROSCOPY ANALYSIS IN NUCLEAR FORENSICS 5. FUNDING NUMBERS 6. AUTHOR(S) Sunny G. Lau 7. PERFORMING ORGANIZATION NAME(S) AND...200 words) The application of resonance ionization mass spectroscopy (RIMS) to nuclear forensics involves the use of lasers to selectively ionize

  3. Application of Laser Induced Breakdown Spectroscopy under Polar Conditions

    Science.gov (United States)

    Clausen, J. L.; Hark, R.; Bol'shakov, A.; Plumer, J.

    2015-12-01

    Over the past decade our research team has evaluated the use of commercial-off-the-shelf laser-induced breakdown spectroscopy (LIBS) for chemical analysis of snow and ice samples under polar conditions. One avenue of research explored LIBS suitability as a detector of paleo-climate proxy indicators (Ca, K, Mg, and Na) in ice as it relates to atmospheric circulation. LIBS results revealed detection of peaks for C and N, consistent with the presence of organic material, as well as major ions (Ca, K, Mg, and Na) and trace metals (Al, Cu, Fe, Mn, Ti). The detection of Ca, K, Mg, and Na confirmed that LIBS has sufficient sensitivity to be used as a tool for characterization of paleo-climate proxy indicators in ice-core samples. Techniques were developed for direct analysis of ice as well as indirect measurements of ice via melting and filtering. Pitfalls and issues of direct ice analysis using several cooling techniques to maintain ice integrity will be discussed. In addition, a new technique, laser ablation molecular isotopic spectroscopy (LAMIS) was applied to detection of hydrogen and oxygen isotopes in ice as isotopic analysis of ice is the main tool in paleoclimatology and glaciology studies. Our results demonstrated that spectra of hydroxyl isotopologues 16OH, 18OH, and 16OD can be recorded with a compact spectrograph to determine hydrogen and oxygen isotopes simultaneously. Quantitative isotopic calibration for ice analysis can be accomplished using multivariate chemometric regression as previously realized for water vapor. Analysis with LIBS and LAMIS required no special sample preparation and was about ten times faster than analysis using ICP-MS. Combination of the two techniques in one portable instrument for in-field analysis appears possible and would eliminate the logistical and cost issues associated with ice core management.

  4. Novel Applications of Laser-Induced Breakdown Spectroscopy.

    Science.gov (United States)

    Bauer, Amy J Ray; Buckley, Steven G

    2017-04-01

    The goal of this review article is to provide a description of recent and novel laser-induced breakdown spectroscopy (LIBS) applications and developments, especially those discussed during the NASLIBS Conference, held during SciX in Providence, RI, in September 2015. This topic was selected in view of the numerous recent overall review papers that have successfully given a broad view of the current understanding of laser-material interactions and plasma development and have also discussed the wide landscape of analytical applications of LIBS. This paper is divided into sections that focus on a few of the many applications under development in the LIBS community. We provide a summary of updates to calibration-free LIBS (CF-LIBS) and associated developments using plasma characteristics to improve quantification in LIBS output, both in a dedicated section and as applications are discussed. We have also described the most recent publications studying the sources, generation, and use of molecular features in LIBS, including those naturally present in the spectra of organic materials, and those induced with the addition of salts to enable the measurement of halogens, not typically present in LIBS signals. In terms of development of applications of LIBS, we focused on the use of LIBS for indirect measurements such as pH and degree of humification in soil and heating value in coal. We also reviewed the extant literature on LIBS analysis of agricultural materials, coal, minerals, and metals. Finally, we discuss the nascent developments of spatially heterodyne spectroscopy, a method that seeks to circumnavigate a serious drawback of most spectrometers - very small optical throughput - through the use of interferometers.

  5. Remote sensing of atmospheric trace gases by diode laser spectroscopy

    Science.gov (United States)

    Liu, Jianguo; Kan, Ruifeng; He, Yabai; He, Ying; Zhang, Yujun; Xie, Pinhua; liu, Wenqing

    2016-04-01

    Gaseous ammonia is the most abundant alkaline trace gas in the atmosphere. In order to study its role in acid deposition and aerosol formation, as well as its influence on the regional air quality and atmospheric visibility, several instruments has been developed based on TDLAS (Tunable Diode Laser Absorption Spectroscopy) techniques. In this paper, a long open path TDLAS system and a continuous-wave CRDS (Cavity-Ring down Spectroscopy) system are presented. The long open path system has been developed for NH3 in-situ monitoring by combining wavelength modulation with harmonic detection techniques to obtain the necessary detection sensitivity. The prototype instrument has been used to monitor atmospheric NH3 concentration at an urban site near Beijing National Stadium during Beijing Olympics in 2008, and recently used to measure the fluxes of NH3 from farm fields by flux-gradient method. The detection limit for ammonia is proved approximately 3ppb for a total path length of 456m. The continuous-wave, rapidly swept CRDS system has been developed for localized atmospheric sensing of trace gases at remote sites. Passive open-path optical sensor units could be coupled by optical fiber over distances of >1 km to a single transmitter/receiver console incorporating a photodetector and a swept-frequency diode laser tuned to molecule-specific near-infrared wavelengths. A noise-limited minimum detectable mixing ratio of ~11 ppbv is attained for ammonia at atmospheric pressure. The developed instruments are deployable in agricultural, industrial, and natural atmospheric environments.

  6. Intracavity laser absorption spectroscopy detection of HCO radicals in atmospheric pressure hydrocarbon flames

    Science.gov (United States)

    Cheskis, Sergey

    1995-01-01

    Formyl radical, HCO, was monitored for the first time in an atmospheric pressure premixed hydrocarbon flame. Intracavity laser absorption spectroscopy based on quasi-(cw) argon-ion pumped dye laser was used. The sensitivity of the detection is ˜5×1012 cm-3 and can be improved with better flame and laser stabilization.

  7. Frequency-comb-assisted broadband precision spectroscopy with cascaded diode lasers

    DEFF Research Database (Denmark)

    Liu, Junqiu; Brasch, Victor; Pfeiffer, Martin H. P.;

    2016-01-01

    Frequency-comb-assisted diode laser spectroscopy, employing both the accuracy of an optical frequency comb and the broad wavelength tuning range of a tunable diode laser, has been widely used in many applications. In this Letter, we present a novel method using cascaded frequency agile diode lasers...

  8. Combining PLS regression with portable NIR spectroscopy to on-line monitor quality parameters in intact olives for determining optimal harvesting time.

    Science.gov (United States)

    Fernández-Espinosa, Antonio J

    2016-01-01

    This study presents a systematized method for predicting water content, fat content and free acidity in olive fruits by on-line NIR Spectroscopy combined with chemometric techniques (PCA, LDA and PLSR). Three cultivar varieties of Olea europaea - Hojiblanca cv., Picual cv. and Arbequina cv. - were monitored. Five olive cultivation areas of Southern Spain (Andalucia) and Southern Portugal (Alentejo) were studied in 2011 and 2012. 465 olive samples were collected during the ripening process (non-mature olives) and compared with other 203 samples of mature olives collected at the final ripening stage. NIR spectra were measured directly in the olive fruits in the wavelength region from 1000 to 2300 nm in reflectance mode. The reference analyses were performed on the olive paste by oven drying for the moisture, by mini-Soxhlet extraction for the fat content and by acid titration of the oil extracted from the olive paste. Calibrations and predictive models were developed by Partial Least Square Regression (PLSR) previous Principal Component and Linear Discriminant analyses (PCA and LDA) were employed as exploratory and clean-up tools of data sets. The final models obtained for the total samples showed acceptable statistics of prediction with R(2)=0.88, RMSEV%=4.88 and RMSEP%=4.98 for water content, R(2)=0.76, RMSECV%=19.5 and RMSEP%=20.0 for fat content and R(2)=0.83, RMSECV%=36.8 and RMSEP%=38.8 for free acidity. Regression coefficients were better for only one maturity state (ripe period) than for olive fruit with different composition (ripening period). All models obtained were applied to predict LQPs on a new set of samples with satisfactory results, a good prediction potential of the models.

  9. Feasibility Study of Using High-Temperature Raman Spectroscopy for On-Line Monitoring and Product Control of the Glass Vitrification Process

    Energy Technology Data Exchange (ETDEWEB)

    Windisch, C.F. Jr.; Piepel, G.F.; Li, H.; Elliott, M.L.; Su, Y.

    1999-01-04

    A pulse-gating Raman spectroscopy setup was developed in this project. The setup was capable of performing in-situ high-temperature Raman measurements for glasses at temperatures as high as 1412 C. In the literature, high-temperature Raman measurements have only been performed on thin films of glass to minimize black-body radiation effects. The pulse-gating Raman setup allows making high-temperature measurements for bulk melts while effectively minimizing black-body radiation effects. A good correlation was found between certain Raman characteristic parameters and glass melt temperature for sodium silicate glasses measured in this project. Comparisons were made between the high-temperature Raman data from this study and literature data. The results suggest that an optimization of the pulse-gating Raman setup is necessary to further improve data quality (i.e., to obtain data with a higher signal-to-noise ratio). An W confocal Raman microspectrometer with continuous wave laser excitation using a 325 nm excitation line was evaluated selectively using a transparent silicate glass ad a deep-colored high-level waste glass in a bulk quantity. The data were successfully collected at temperatures as high as approximately 1500 C. The results demonstrated that the UV excitation line can be used for high-temperature Raman measurements of molten glasses without black-body radiation interference from the melt for both transparent and deep-color glasses. Further studies are needed to select the best laser system that can be used to develop high-temperature Raman glass databases.

  10. Laser-frequency locking using light-pressure-induced spectroscopy in a calcium beam

    NARCIS (Netherlands)

    Mollema, A. K.; Wansbeek, L. W.; Willmann, L.; Jungmann, K.; Timmermans, R. G. E.; Hoekstra, R.

    We demonstrate a spectroscopy method that can be applied in an atomic beam, light-pressure-induced spectroscopy (LiPS). A simple pump and probe experiment yields a dispersivelike spectroscopy signal that can be utilized for laser frequency stabilization. The underlying principles are discussed and

  11. Fast analysis of wood preservers using laser induced breakdown spectroscopy

    Science.gov (United States)

    Uhl, A.; Loebe, K.; Kreuchwig, L.

    2001-06-01

    Laser-induced breakdown spectroscopy (LIBS) is used for the investigation of wood preservers in timber and in furniture. Both experiments in laboratory and practical applications in recycling facilities and on a building site prove the new possibilities for the fast detection of harmful agents in wood. A commercial system was developed for mobile laser-plasma-analysis as well as for industrial use in sorting plants. The universal measuring principle in combination with an Echelle optics permits real simultaneous multi-element-analysis in the range of 200-780 nm with a resolution of a few picometers. It enables the user to detect main and trace elements in wood within a few seconds, nearly independent of the matrix, knowing that different kinds of wood show an equal elemental composition. Sample preparation is not required. The quantitative analysis of inorganic wood preservers (containing, e.g. Cu, Cr, B, As, Pb, Hg) has been performed exactly using carbon as reference element. It can be shown that the detection limits for heavy metals in wood are in the ppm-range. Additional information is given concerning the quantitative analysis. Statistical data, e.g. the standard deviation (S.D.), were determined and calibration curves were used for each particular element. A comparison between ICP-AES and LIBS is given using depth profile correction factors regarding the different penetration depths with respect to the different volumes in wood analyzed by both analytical methods.

  12. Laser Spectroscopy Studies in the Neutron-Rich Sn Region

    CERN Multimedia

    Obert, J

    2002-01-01

    We propose to use the powerful laser spectroscopy method to determine the magnetic moment $\\mu$ and the variation of the mean square charge radius ($\\delta\\,\\langle$r$_{c}^{2}\\,\\rangle$) for ground and long-lived isomeric states of the Sn isotopes from A=125 to the doubly-magic $^{132}$Sn isotope and beyond. For these neutron-rich Sn nuclei, numerous $\\delta\\,\\langle$r$^{2}_{c}\\,\\rangle$ curves have already been calculated and the predictions depend upon the effective interactions used. Therefore, a study of the effect of the shell closure N=82 on the $\\delta\\,\\langle$r$^{2}_{c}\\,\\rangle$ values in the Z=50 magic nuclei is of great interest, especially because $^{132}$Sn is located far from the stability valley. It will help to improve the parameters of the effective interactions and make them more suitable to predict the properties of exotic nuclei. \\\\ \\\\The neutron-rich Sn isotopes produced with an uranium carbide target, are ionized using either a hot plasma ion source or the resonant ionization laser ion ...

  13. Laser Raman Spectroscopy in studies of corrosion and electrocatalysis

    Energy Technology Data Exchange (ETDEWEB)

    Melendres, C.A.

    1988-01-01

    Laser Raman Spectroscopy (LRS) has become an important tool for the in-situ structural study of electrochemical systems and processes in recent years. Following a brief introduction of the experimental techniques involved in applying LRS to electrochemical systems, we survey the literature for examples of studies in the inhibition of electrode reactions by surface films (e.g., corrosion and passivation phenomena) as well as the acceleration of reactions by electro-sorbates (electrocatalysis). We deal mostly with both normal and resonance Raman effects on fairly thick surface films in contrast to surface-enhanced Raman investigations of monolayer adsorbates, which is covered in another lecture. Laser Raman spectroelectrochemical studies of corrosion and film formation on such metals as Pb, Ag, Fe, Ni, Co, Cr, Au, stainless steel, etc. in various solution conditions are discussed. Further extension of the technique to studies in high-temperature and high-pressure aqueous environments is demonstrated. Results of studies of the structure of corrosion inhibitors are also presented. As applications of the LRS technique in the area of electrocatalysis, we cite studies of the structure of transition metal macrocyclic compounds, i.e., phthalocyanines and porphyrins, used for catalysis of the oxygen reduction reaction. 104 refs., 20 figs.

  14. 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.

  15. Tunable diode laser spectroscopy as a technique for combustion diagnostics

    Energy Technology Data Exchange (ETDEWEB)

    Bolshov, M.A., E-mail: bolshov@isan.troitsk.ru; Kuritsyn, Yu.A.; Romanovskii, Yu.V.

    2015-04-01

    Tunable diode laser absorption spectroscopy (TDLAS) has become a proven method of rapid gas diagnostics. In the present review an overview of the state of the art of TDL-based sensors and their applications for measurements of temperature, pressure, and species concentrations of gas components in harsh environments is given. In particular, the contemporary tunable diode laser systems, various methods of absorption detection (direct absorption measurements, wavelength modulation based phase sensitive detection), and relevant algorithms for data processing that improve accuracy and accelerate the diagnostics cycle are discussed in detail. The paper demonstrates how the recent developments of these methods and algorithms made it possible to extend the functionality of TDLAS in the tomographic imaging of combustion processes. Some prominent examples of applications of TDL-based sensors in a wide range of practical combustion aggregates, including scramjet engines and facilities, internal combustion engines, pulse detonation combustors, and coal gasifiers, are given in the final part of the review. - Highlights: • Overview of modern TDL-based sensors for combustion • TDL systems, methods of absorption detection and algorithms of data processing • Prominent examples of TDLAS diagnostics of the combustion facilities • Extension of the TDLAS on the tomographic imaging of combustion processes.

  16. [Rapid detection of chlorinated organic mixture by laser Raman spectroscopy].

    Science.gov (United States)

    Ma, Jing

    2014-07-01

    In order to realize the rapid, nondestructive detection of organic compounds, a two-dimensional analysis method based on technology of laser Raman spectroscopy was proposed. The results show that using 532 nm laser as excitation light source, the observation of 236.2, 348.9, 449.4 and 513.6 cm(-1), the four vibrational Raman spectra, and the intensity ratio of 6.4 : 1.7: 9.4 : 1.0 can determine the existence of tetrachloroethylene. The observation of 707.5, 1 087.9, 1 175.8 and 3 078.6 cm(-1), the four vibrational Raman spectra, and the intensity ratio of 9.6 : 6.4 : 1.0 : 3.9 can determine the existence of chlorobenzene. In other words, that through the comprehensive study of spectral lines and intensity ratio of some spectral lines, the presence of organic compounds in the mixed solution can be determined quickly. In the aspect of quantitative analysis, using multi-spectral analysis combined with least square fitting method can improve the reliability of the measurement, The accuracy of sample concentration was 98.4%. This spectral measurement method is a potential tool for organic component identification and concentration analysis which has a prosperous application prospects.

  17. Laser-induced breakdown spectroscopy for polymer identification.

    Science.gov (United States)

    Grégoire, Sylvain; Boudinet, Marjorie; Pelascini, Frédéric; Surma, Fabrice; Detalle, Vincent; Holl, Yves

    2011-07-01

    This study aims at differentiating several organic materials, particularly polymers, by laser induced breakdown spectroscopy. The goal is to apply this technique to the fields of polymer recycling and cultural heritage conservation. We worked with some usual polymers families: polyethylene (PE), polypropylene (PP), polyoxymethylene, (POM), poly(vinyl chloride), polytetrafluoroethylene, polyoxyethylene (POE), and polyamide for the aliphatic ones, and poly(butylene terephthalate), acrylonitrile-butadiene-styrene, polystyrene, and polycarbonate for the aromatic ones. The fourth harmonic of a Nd:YAG laser (266 nm) in ambient air at atmospheric pressure was used. A careful analysis of the C(2) Swan system (0,0) band in polymers containing no C-C (POM), few C-C (POE), or aromatic C-C linkages led us to the conclusion that the C(2) signal might be native, i.e., the result of direct ablation from the sample. With use of these results, aliphatic and aromatic polymers could be differentiated. Further data treatments, such as properly chosen line ratios, principal component analysis, and partial least squares regression, were evaluated. It was shown that many polymers could be separated, including PE and PP, despite their similar chemical structures.

  18. Unsupervised verification of laser-induced breakdown spectroscopy dataset clustering

    Science.gov (United States)

    Wójcik, Michał R.; Zdunek, Rafał; Antończak, Arkadiusz J.

    2016-12-01

    Laser-induced breakdown spectroscopy is a versatile, optical technique used in a wide range of qualitative and quantitative analyses conducted with the use of various chemometric techniques. The aim of this research is to demonstrate the possibility of unsupervised clustering of an unknown dataset using K-means clustering algorithm, and verifying its input parameters through investigating generalized eigenvalues derived with linear discriminant analysis. In all the cases, principal component analyses have been applied to reduce data dimensionality and shorten computation time of the whole operation. The experiment was conducted on a dataset collected from twenty four different materials divided into six groups: metals, semiconductors, ceramics, rocks, metal alloys and others with the use of a three-channel spectrometer (298.02-628.73nm overall spectral range) and a UV (248nm) excimer laser. Additionally, two more complex groups containing all specimens and all specimens excluding rocks were created. The resulting spaces of eigenvalues were calculated for every group and three different distances in the multidimensional space (cosine, square Euclidean and L1). As expected, the correct numbers of specimens within groups with small deviations were obtained, and the validity of the unsupervised method has thus been proven.

  19. Application of laser Raman spectroscopy to dental diagnosis

    Science.gov (United States)

    Izawa, Takahiro; Wakaki, Moriaki

    2005-03-01

    The aim of this research is related with the diagnosis of caries by use of a laser. We study the fundamental characterization of the diagnosis method using both fluorescence and Raman scattering spectroscopy. We try to evaluate the possibility of the caries diagnosis using Raman spectroscopy and its clinical application. We focus on the PO34- ion that flows out with the dissolution of hydroxyapatite (HAp), and the fluorescence that increases in connection with caries. The Raman line of P-O vibration is overlapped on the continuous, background spectrum by fluorescence. Consequently, we try to find out the correlation between a healthy part and a carious part by analyzing both fluorescence and Raman spectra. It was found that Raman intensity of HAp at carious lesion was weaker than those of healthy parts and the florescence intensity at the same portions was stronger. We have obtained the feasibility to estimate the degree of caries and health condition by deriving the ratio between Raman and florescence intensity. And the trial measurements in vivo were carried out to verify the availability of the method by using a fiber probe type multi channel Raman spectrometer. The process of remineralization is under researching for the development of preventive medicine.

  20. Single fiber laser based wavelength tunable excitation for CRS spectroscopy.

    Science.gov (United States)

    Su, Jue; Xie, Ruxin; Johnson, Carey K; Hui, Rongqing

    2013-06-01

    We demonstrate coherent Raman spectroscopy (CRS) using a tunable excitation source based on a single femtosecond fiber laser. The frequency difference between the pump and the Stokes pulses was generated by soliton self-frequency shifting (SSFS) in a nonlinear optical fiber. Spectra of C-H stretches of cyclohexane were measured simultaneously by stimulated Raman gain (SRG) and coherent anti-Stokes Raman scattering (CARS) and compared. We demonstrate the use of spectral focusing through pulse chirping to improve CRS spectral resolution. We analyze the impact of pulse stretching on the reduction of power efficiency for CARS and SRG. Due to chromatic dispersion in the fiber-optic system, the differential pulse delay is a function of Stokes wavelength. This differential delay has to be accounted for when performing spectroscopy in which the Stokes wavelength needs to be scanned. CARS and SRG signals were collected and displayed in two dimensions as a function of both the time delay between chirped pulses and the Stokes wavelength, and we demonstrate how to find the stimulated Raman spectrum from the two-dimensional plots. Strategies of system optimization consideration are discussed in terms of practical applications.

  1. Biomonitoring of essential and toxic metals in single hair using on-line solution-based calibration in laser ablation inductively coupled plasma mass spectrometry.

    Science.gov (United States)

    Dressler, Valderi L; Pozebon, Dirce; Mesko, Marcia Foster; Matusch, Andreas; Kumtabtim, Usarat; Wu, B; Sabine Becker, J

    2010-10-15

    Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) has been established as a powerful and sensitive surface analytical technique for the determination of concentration and distribution of trace metals within biological systems at micrometer spatial resolution. LA-ICP-MS allows easy quantification procedures if suitable standard references materials (SRM) are available. In this work a new SRM-free approach of solution-based calibration method in LA-ICP-MS for element quantification in hair is described. A dual argon flow of the carrier gas and nebulizer gas is used. A dry aerosol produced by laser ablation (LA) of biological sample and a desolvated aerosol generated by pneumatic nebulization (PN) of standard solutions are carried by two different flows of argon as carrier or nebulizer gas, respectively and introduced separately in the injector tube of a special ICP torch, through two separated apertures. Both argon flows are mixed directly in the ICP torch. External calibration via defined standard solutions before analysis of single hair was employed as calibration strategy. A correction factor, calculated using hair with known analyte concentration (measured by ICP-MS), is applied to correct the different elemental sensitivities of ICP-MS and LA-ICP-MS. Calibration curves are obtained by plotting the ratio of analyte ion M(+)/(34)S(+) ion intensities measured using LA-ICP-MS in dependence of analyte concentration in calibration solutions. Matrix-matched on-line calibration in LA-ICP-MS is carried out by ablating of human hair strands (mounted on a sticky tape in the LA chamber) using a focused laser beam in parallel with conventional nebulization of calibration solutions. Calibrations curves of Li, Na, Mg, Al, K, V, Cr, Mn, Fe, Ni, Co, Cu, Zn, Sr, Mo, Ag, Cd, I, Hg, Pb, Tl, Bi and U are presented. The linear correlation coefficients (R) of calibration curves for analytes were typically between 0.97 and 0.999. The limits of detection (LODs) of

  2. Comparative investigation of laser-induced breakdown spectroscopy in bulk water using 532- and 1064-nm lasers

    Science.gov (United States)

    Tian, Ye; Xue, Boyang; Song, Jiaojian; Lu, Yuan; Li, Ying; Zheng, Ronger

    2017-07-01

    The influence of laser wavelength on the characteristics of laser-induced breakdown spectroscopy (LIBS) in bulk water was investigated by using 532- and 1064-nm lasers. We demonstrated that higher laser energy does not lead to higher LIBS signals because of the strong plasma shielding occurring at high laser energies, as shown by the spectroscopic and fast imaging results in this work. At threshold energies of 100% breakdown probability, the 1064 nm beam could induce a plasma with higher electron density and temperature than the 532 nm beam, which leads to higher signal-to-noise ratios and longer lifetimes of the emission lines.

  3. Laser ablation-laser induced breakdown spectroscopy for the measurement of total elemental concentration in soils.

    Science.gov (United States)

    Pareja, Jhon; López, Sebastian; Jaramillo, Daniel; Hahn, David W; Molina, Alejandro

    2013-04-10

    The performances of traditional laser-induced breakdown spectroscopy (LIBS) and laser ablation-LIBS (LA-LIBS) were compared by quantifying the total elemental concentration of potassium in highly heterogeneous solid samples, namely soils. Calibration curves for a set of fifteen samples with a wide range of potassium concentrations were generated. The LA-LIBS approach produced a superior linear response different than the traditional LIBS scheme. The analytical response of LA-LIBS was tested with a large set of different soil samples for the quantification of the total concentration of Fe, Mn, Mg, Ca, Na, and K. Results showed an acceptable linear response for Ca, Fe, Mg, and K while poor signal responses were found for Na and Mn. Signs of remaining matrix effects for the LA-LIBS approach in the case of soil analysis were found and discussed. Finally, some improvements and possibilities for future studies toward quantitative soil analysis with the LA-LIBS technique are suggested.

  4. Chirped laser dispersion spectroscopy for laser-based hydrogen sulfide detection in open-path conditions.

    Science.gov (United States)

    Nikodem, Michał

    2016-05-16

    In this paper the design and characterization of a near-IR Chirped Laser Dispersion Spectroscopy (CLaDS)-based setup for hydrogen sulfide (H2S) detection is reported. This system can be implemented for open-path sensing also in standoff configuration. Target transition selection, system noise and detection limit are discussed and characterized. Furthermore, the cross-interference with other molecules is analyzed. CLaDS-based detection is shown to be highly immune to background carbon dioxide changes, which is a critical issue in accurate open-path sensing of hydrogen sulfide.

  5. Time-Resolved Spectroscopy Diagnostic of Laser-Induced Optical Breakdown

    OpenAIRE

    Parigger, Christian G.; Hornkohl, James O.; László Nemes

    2010-01-01

    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 ...

  6. Two-dimensional fluorescence spectroscopy of uranium isotopes in femtosecond laser ablation plumes

    Energy Technology Data Exchange (ETDEWEB)

    Phillips, Mark C.; Brumfield, Brian E.; LaHaye, Nicole L.; Harilal, Sivanandan S.; Hartig, Kyle C.; Jovanovic, Igor

    2017-06-19

    We demonstrate measurement of uranium isotopes in femtosecond laser ablation plumes using two-dimensional fluorescence spectroscopy (2DFS). The high-resolution, tunable CW-laser spectroscopy technique clearly distinguishes atomic absorption from 235U and 238U in natural and highly enriched uranium metal samples. We present analysis of spectral resolution and analytical performance of 2DFS as a function of ambient pressure. Simultaneous measurement using time-resolved absorption spectroscopy provides information on temporal dynamics of the laser ablation plume and saturation behavior of fluorescence signals. The rapid, non-contact measurement is promising for in-field, standoff measurements of uranium enrichment for nuclear safety and security applications.

  7. Laser-induced atomic fragment fluorescence spectroscopy: a facile technique for molecular spectroscopy of spin-forbidden states.

    Science.gov (United States)

    Zhang, Qun; Chen, Yang; Keil, Mark

    2009-03-01

    Spectra of spin-forbidden and spin-allowed transitions in the mixed b (3)Pi(u) approximately A (1)Sigma(u)(+) state of Na(2) are measured separately by two-photon excitation using a single tunable dye laser. The two-photon excitation produces Na(*)(3p) by photodissociation, which is easily and sensitively detected by atomic fluorescence. At low laser power, only the A (1)Sigma(u)(+) state is excited, completely free of triplet excitation. At high laser power, photodissociation via the intermediate b (3)Pi(u) triplet state becomes much more likely, effectively "switching" the observations from singlet spectroscopy to triplet spectroscopy with only minor apparatus changes. This technique of perturbation-assisted laser-induced atomic fragment fluorescence may therefore be especially useful as a general vehicle for investigating perturbation-related physics pertinent to the spin-forbidden states, as well as for studying allowed and forbidden states of other molecules.

  8. Application of laser-induced breakdown spectroscopy to zirconium in aqueous solution

    Science.gov (United States)

    Ruas, Alexandre; Matsumoto, Ayumu; Ohba, Hironori; Akaoka, Katsuaki; Wakaida, Ikuo

    2017-05-01

    In the context of the Fukushima Dai-ichi Nuclear Power Plant (F1-NPP) decommissioning process, laser-induced breakdown spectroscopy (LIBS) has many advantages. The purpose of the present work is to demonstrate the on-line monitoring capability of the LIBS coupled with the ultra-thin liquid jet sampling method. The study focuses on zirconium in aqueous solution, considering that it is a major element in the F1-NPP fuel debris that has been subject to only a few LIBS studies in the past. The methodology of data acquisition and processing are described. In particular, two regions of interest with many high intensity zirconium lines have been observed around 350 nm in the case of the ionic lines and 478 nm in the case of atomic lines. The best analytical conditions for zirconium are different depending on the analysis of ionic lines or atomic lines. A low LOD of about 4 mg L- 1 could be obtained, showing that LIBS coupled with the ultra-thin liquid jet sampling technique is a promising alternative for more complex solutions found in the F1-NPP, namely mixtures containing zirconium.

  9. [Monitoring the change in CO concentration in combustion with tunable diode laser absorption spectroscopy].

    Science.gov (United States)

    Xia, Hui; Liu, Wen-Qing; Zhang, Yu-Jun; Kan, Rui-Feng; Chen, Dong; Cui, Yi-Ben; He, Ying; Chen, Jiu-Ying; Wang, Min; Wang, Tie-Dong

    2008-11-01

    In the present paper, the technology of tunable diode laser absorption spectroscopy (TDLAS) in conjunction with the open path multi-pass Herriot cell and the new-style detection method of auto-balanced detection combined with wavelength modulation technology were used, and the concentration of CO produced in combustion of alcohol blowtorch was measured. It was found in the measured result that the change in CO concentration in the flame of alcohol blowtorch presented a stated periodicity in the process of combustion and the average concentration of CO was calculated to be 49.4 (10(-6) ratio by volume). The experiment is showed that with the conjunction of auto-balanced detection and the second harmonics detection method, adopting the open path multi-pass Herrriot cell to detect the concentration of CO in the combustion of alcohol blowtorch is accurate and contents the detection requirement. It was proved that the system made for measuring the concentration of CO in the flame of alcohol blowtorch in combustion establishes foundation well for developing on-line combustion monitoring based on TDLAS.

  10. Large odd-even staggering in the very light platinum isotopes from laser spectroscopy

    CERN Document Server

    Le Blanc, F; Cabaret, L A; Crawford, J E; Duong, H T; Genevey, J; Girod, M; Huber, G; Krieg, M; Lee, J K P; Lettry, Jacques; Lunney, M D; Obert, J; Oms, J; Peru, S; Putaux, J C; Roussière, B; Sauvage, J; Sebastian, V; Zemlyanoi, S G

    1998-01-01

    Laser spectroscopy measurements have been carried out on very neutron-deficient platinum isotopes with the COMPLIS experimental set-up on line with the ISOLDE-Booster facility. For the first time, Hg alpha -decay was exploited to extend the very light platinum chain. Using the 5d/sup 9/6s /sup 3/D/sub 3/ to 5d/sup 9/6p /sup 3/P /sub 2/ optical transition, hyperfine spectra of /sup 182,181,180,179,178/Pt and /sup 183/Pt/sup m/ were recorded for the first time. The variation of the mean square charge radius between these nuclei, the magnetic moments of the odd isotopes and the quadrupole moment of /sup 183/Pt/sup m/ were thus measured. A large deformation change between /sup 183/Pt/sup 9/ and /sup 183/Pt/sup m/, an odd-even staggering of the charge radius and a deformation drop from A=179 are clearly observed. All these results are discussed and compared with microscopic theoretical predictions using Hartree-Fock- Bogolyubov calculations using the Gogny force. (20 refs).

  11. Micro spatial analysis of seashell surface using laser-induced breakdown spectroscopy and Raman spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Yuan; Li, Yuandong; Li, Ying [Optics and Optoelectronics Lab, Ocean University of China, Qingdao 266100 (China); Wang, Yangfan; Wang, Shi; Bao, Zhenmin [Life Science College, Ocean University of China, Qingdao 266003 (China); Zheng, Ronger, E-mail: rzheng@ouc.edu.cn [Optics and Optoelectronics Lab, Ocean University of China, Qingdao 266100 (China)

    2015-08-01

    The seashell has been studied as a proxy for the marine researches since it is the biomineralization product recording the growth development and the ocean ecosystem evolution. In this work a hybrid of Laser Induced Breakdown Spectroscopy (LIBS) and Raman spectroscopy was introduced to the composition analysis of seashell (scallop, bivalve, Zhikong). Without any sample treatment, the compositional distribution of the shell was obtained using LIBS for the element detection and Raman for the molecule recognition respectively. The elements Ca, K, Li, Mg, Mn and Sr were recognized by LIBS; the molecule carotene and carbonate were identified with Raman. It was found that the LIBS detection result was more related to the shell growth than the detection result of Raman. The obtained result suggested the shell growth might be developing in both horizontal and vertical directions. It was indicated that the LIBS–Raman combination could be an alternative way for the shell researches. - Highlights: • A LIBS–Raman hybrid system was developed. • A seashell has been analyzed for the elementary and molecular distribution with a system. • The shell growth development was studied on the surface and in the depth.

  12. Self-calibration wavelength modulation spectroscopy for acetylene detection based on tunable diode laser absorption spectroscopy

    Science.gov (United States)

    Huang, Qin-Bin; Xu, Xue-Mei; Li, Chen-Jing; Ding, Yi-Peng; Cao, Can; Yin, Lin-Zi; Ding, Jia-Feng

    2016-11-01

    The expressions of the second harmonic (2f) signal are derived on the basis of absorption spectral and lock-in theories. A parametric study indicates that the phase shift between the intensity and wavelength modulation makes a great contribution to the 2f signal. A self-calibration wavelength modulation spectroscopy (WMS) method based on tunable diode laser absorption spectroscopy (TDLAS) is applied, combining the advantages of ambient pressure, temperature suppression, and phase-shift influences elimination. Species concentration is retrieved simultaneously from selected 2f signal pairs of measured and reference WMS-2f spectra. The absorption line of acetylene (C2H2) at 1530.36 nm near-infrared is selected to detect C2H2 concentrations in the range of 0-400 ppmv. System sensitivity, detection precision and limit are markedly improved, demonstrating that the self-calibration method has better detecting performance than the conventional WMS. Project supported by the National Natural Science Foundation of China (Grant Nos. 61172047, 61502538, and 61501525).

  13. Portable Infrared Laser Spectroscopy for On-site Mycotoxin Analysis

    Science.gov (United States)

    Sieger, Markus; Kos, Gregor; Sulyok, Michael; Godejohann, Matthias; Krska, Rudolf; Mizaikoff, Boris

    2017-03-01

    Mycotoxins are toxic secondary metabolites of fungi that spoil food, and severely impact human health (e.g., causing cancer). Therefore, the rapid determination of mycotoxin contamination including deoxynivalenol and aflatoxin B1 in food and feed samples is of prime interest for commodity importers and processors. While chromatography-based techniques are well established in laboratory environments, only very few (i.e., mostly immunochemical) techniques exist enabling direct on-site analysis for traders and manufacturers. In this study, we present MYCOSPEC - an innovative approach for spectroscopic mycotoxin contamination analysis at EU regulatory limits for the first time utilizing mid-infrared tunable quantum cascade laser (QCL) spectroscopy. This analysis technique facilitates on-site mycotoxin analysis by combining QCL technology with GaAs/AlGaAs thin-film waveguides. Multivariate data mining strategies (i.e., principal component analysis) enabled the classification of deoxynivalenol-contaminated maize and wheat samples, and of aflatoxin B1 affected peanuts at EU regulatory limits of 1250 μg kg‑1 and 8 μg kg‑1, respectively.

  14. Analysis of bakery products by laser-induced breakdown spectroscopy.

    Science.gov (United States)

    Bilge, Gonca; Boyacı, İsmail Hakkı; Eseller, Kemal Efe; Tamer, Uğur; Çakır, Serhat

    2015-08-15

    In this study, we focused on the detection of Na in bakery products by using laser-induced breakdown spectroscopy (LIBS) as a quick and simple method. LIBS experiments were performed to examine the Na at 589 nm to quantify NaCl. A series of standard bread sample pellets containing various concentrations of NaCl (0.025-3.5%) were used to construct the calibration curves and to determine the detection limits of the measurements. Calibration graphs were drawn to indicate functions of NaCl and Na concentrations, which showed good linearity in the range of 0.025-3.5% NaCl and 0.01-1.4% Na concentrations with correlation coefficients (R(2)) values greater than 0.98 and 0.96. The obtained detection limits for NaCl and Na were 175 and 69 ppm, respectively. Performed experimental studies showed that LIBS is a convenient method for commercial bakery products to quantify NaCl concentrations as a rapid and in situ technique.

  15. Portable Infrared Laser Spectroscopy for On-site Mycotoxin Analysis

    Science.gov (United States)

    Sieger, Markus; Kos, Gregor; Sulyok, Michael; Godejohann, Matthias; Krska, Rudolf; Mizaikoff, Boris

    2017-01-01

    Mycotoxins are toxic secondary metabolites of fungi that spoil food, and severely impact human health (e.g., causing cancer). Therefore, the rapid determination of mycotoxin contamination including deoxynivalenol and aflatoxin B1 in food and feed samples is of prime interest for commodity importers and processors. While chromatography-based techniques are well established in laboratory environments, only very few (i.e., mostly immunochemical) techniques exist enabling direct on-site analysis for traders and manufacturers. In this study, we present MYCOSPEC - an innovative approach for spectroscopic mycotoxin contamination analysis at EU regulatory limits for the first time utilizing mid-infrared tunable quantum cascade laser (QCL) spectroscopy. This analysis technique facilitates on-site mycotoxin analysis by combining QCL technology with GaAs/AlGaAs thin-film waveguides. Multivariate data mining strategies (i.e., principal component analysis) enabled the classification of deoxynivalenol-contaminated maize and wheat samples, and of aflatoxin B1 affected peanuts at EU regulatory limits of 1250 μg kg−1 and 8 μg kg−1, respectively. PMID:28276454

  16. Study of Bacterial Samples Using Laser Induced Breakdown Spectroscopy

    Science.gov (United States)

    W, A. Farooq; M, Atif; W, Tawfik; M, S. Alsalhi; Z, A. Alahmed; M, Sarfraz; J, P. Singh

    2014-12-01

    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.

  17. Optical humidity detection based on tunable diode laser absorption spectroscopy

    Science.gov (United States)

    Zhang, Keke; Liu, Shixuan; Chen, Shizhe; Zhao, Qiang; Zhang, Lijuan; Li, Xuanqun; Wang, Wenyan; Wu, Yushang

    2017-02-01

    Humidity is an important environmental parameter, which is difficult to be measured accurately and quickly using traditional measurement methods. Under the environment of low temperature or high humidity, traditional humidity and temperature sensor has shortages in humidity measurement accuracy, corresponding time and wet fade speed. To solve these problems, this paper proposes a method to measure the environmental humidity with wavelength modulation technology and harmonic detection technology based on tunable diode laser absorption spectroscopy. H2O molecular absorption line near 1392 nm is selected as the characteristic spectra. The effects of temperature, pressure and water concentration on the absorption spectrum width, the wavelength modulation coefficient and the amplitude of the harmonic signal are analyzed. Humidity and temperature sensor is modified using temperature and pressure compensation model, and the influence of the water concentration variation is eliminated by the iterative algorithm. The new humidity and temperature sensor prototype is developed, and the structure of the optical system is simple, which is easy to be adjusted. The response frequency of the humidity detection is 40 Hz. The experiment was carried out for 3 months at Qingdao national basic weather station. Experimental results show that the consistency of the humidity and temperature data is very good, which can proves the validity of the humidity measurement technology.

  18. Multiphoton Ionization Detection in Collinear Laser Spectroscopy of Isolde Beams

    CERN Multimedia

    2002-01-01

    The experiments using the multiphoton ionization technique have been continued in the beginning of 1990 with stable beam tests on the modified apparatus and with another radioactive beam time on Yb. Higher laser power and an increased vacuum in the ionization region (see figure) yielded a further gain in sensitivity, mainly due to the better suppression of the background ions produced in rest gas collisions. For even Yb isotopes we have now reached a detection efficiency of $\\epsilon$~=~1~x~10$^{-5}$ ions per incoming atom at a background count rate of 30~ions from a beam of 5~x~10$^9$. This sensitivity was high enough for spectroscopy on $^{157}$Yb, where the typical ISOLDE yield of 5~x~10$^7$Yb ions is covered by an isobaric contamination of more than 10$^{10}$ ions. Measurements have also been performed on $^{175}$Yb. These give the first precise value for the magnetic moment of this isotope, $\\mu$~=~0.766(8)$ mu _{N} $, which agrees rather well with the magnetic moment of the isotone $^{177}$Hf. The isoto...

  19. 3D Imaging of Nanoparticle Distribution in Biological Tissue by Laser-Induced Breakdown Spectroscopy

    National Research Council Canada - National Science Library

    Gimenez, Y; Busser, B; Trichard, F; Kulesza, A; Laurent, J M; Zaun, V; Lux, F; Benoit, J M; Panczer, G; Dugourd, P; Tillement, O; Pelascini, F; Sancey, L; Motto-Ros, V

    2016-01-01

    .... The technology used is known as laser-induced breakdown spectroscopy (LIBS) and possesses several advantages such as speed of operation, ease of use and full compatibility with optical microscopy...

  20. Mapping chemical bonding of reaction intermediates with femtosecond X-ray laser spectroscopy

    NARCIS (Netherlands)

    Wernet, P.; Beye, M.; de Groot, F.; Düsterer, S.; Grübel, S.; Gaffney, K.; Hartsock, R.; Hennies, F.; Josefsson, I.; Kennedy, B.; Kunnus, K.; Leitner, T.; Mazza, T.; Meyer, M.; Nordlund, D.; Odelius, M.; Quevedo, W.; Radcliffe, P.; Rajkovic, I.; Schlotter, B.; Scholz, M.; Schreck, S.; Suljoti, E.; Techert, S.; Turner, J.; Weniger, C.; Zhang, W.; Föhlisch, A.

    2013-01-01

    We determine the pathways in the photo-dissociation reactions of Fe(CO)5 both in the gas phase and in solution by mapping the valence electronic structure of the reaction intermediates with femtosecond X-ray laser spectroscopy.

  1. MEASUREMENT OF AMMONIA EMISSIONS FROM MECHANICALLY VENTILATED POULTRY HOUSES USING MULTIPATH TUNABLE DIODE LASER SPECTROSCOPY

    Science.gov (United States)

    Ammonia emissions from mechanically ventilated poultry operations are an important environmental concern. Open Path Tunable Diode Laser Absorption Spectroscopy has emerged as a robust real-time method for gas phase measurement of ammonia concentrations in agricultural settings. ...

  2. Laser Calorimetry Spectroscopy for ppm-level Dissolved Gas Detection and Analysis

    OpenAIRE

    Nagapriya K. S.; Shashank Sinha; Prashanth R.; Samhitha Poonacha; Gunaranjan Chaudhry; Anandaroop Bhattacharya; Niloy Choudhury; Saroj Mahalik; Sandip Maity

    2017-01-01

    In this paper we report a newly developed technique – laser calorimetry spectroscopy (LCS), which is a combination of laser absorption spectroscopy and calorimetry - for the detection of gases dissolved in liquids. The technique involves determination of concentration of a dissolved gas by irradiating the liquid with light of a wavelength where the gas absorbs, and measuring the temperature change caused by the absorbance. Conventionally, detection of dissolved gases with sufficient sensitivi...

  3. Multivariate Analysis of Laser-Induced Breakdown Spectroscopy for Discrimination between Explosives and Plastics

    Institute of Scientific and Technical Information of China (English)

    WANG Qian-Qian; LIU Kai; ZHAO Hua

    2012-01-01

    A method to distinguish explosives from plastics using laser-induced breakdown spectroscopy is discussed. A model for classification with cross-validation theory is built based on the partial least-square discriminant analysis method. Seven types of plastics and one explosive are used as samples to test the model. The experimental results demonstrate that laser-induced breakdown spectroscopy has the capacity to discriminate explosives from plastics combined with chemometrics methods. The results could be useful for prospective research of laser-induced breakdown spectroscopy on the differentiation of explosives and other materials.%A method to distinguish explosives from plastics using laser-induced breakdown spectroscopy is discussed.A model for classification with cross-validation theory is built based on the partial least-square discriminant analysis method.Seven types of plastics and one explosive are used as samples to test the model.The experimental results demonstrate that laser-induced breakdown spectroscopy has the capacity to discriminate explosives from plastics combined with chemometrics methods.The results could be useful for prospective research of laser-induced breakdown spectroscopy on the differentiation of explosives and other materials.

  4. Frontiers of QC Laser spectroscopy for high precision isotope ratio analysis of greenhouse gases

    Science.gov (United States)

    Emmenegger, Lukas; Mohn, Joachim; Harris, Eliza; Eyer, Simon; Ibraim, Erkan; Tuzson, Béla

    2016-04-01

    11, 1685-1696 (2011). 3 Mohn, J. et al. A liquid nitrogen-free preconcentration unit for measurements of ambient N2O isotopomers by QCLAS. Atmospheric Measurement Techniques 3, 609-618 (2010). 4 Wolf, B. et al. First on-line isotopic characterization of N2O above intensively managed grassland. Biogeosciences 12, 2517-1960 (2015). 5 Harris, E. et al. Nitrous oxide and methane emissions and nitrous oxide isotopic composition from waste incineration in Switzerland. Waste Management 35, 135-140 (2015). 6 Harris, E. et al. Isotopic evidence for nitrous oxide production pathways in a partial nitritation-anammox reactor. Water Research 83, 258-270 (2015). 7 Eyer, S. et al. Real-time analysis of δ13C- and δ D-CH4 in ambient air with laser spectroscopy: method development and first intercomparison results. Atmos. Meas. Tech. Discuss. 8, 8925-8970 (2015).

  5. First measurement of radioisotopes by collinear laser spectroscopy at an ion-guide separator

    NARCIS (Netherlands)

    Cooke, JL; Billowes, J; Campbell, P; Cochrane, ECA; Cooper, TG; Dendooven, P; Evans, DE; Griffith, JAR; Grant, IS; Honkanen, A; Huhta, M; Levins, JMG; Oinonen, M; Pearson, MR; Penttila, H; Persson, B.L.; Richardson, DS; Tungate, G; Wheeler, PD; Zybert, L; Aysto, J

    1997-01-01

    The first successful application of an ion-guide separator (IGISOL) for collinear laser spectroscopy of radioisotopes has achieved an efficiency comparable with the best obtained with catcher-ionizer facilities. The ion beam energy spread was determined to be less than 6 eV, allowing laser fluoresce

  6. First collinear laser spectroscopy measurements of radioisotopes from an IGISOL ion source

    NARCIS (Netherlands)

    Billowes, J; Campbell, P; Cochrane, ECA; Cooke, JL; Dendooven, P; Evans, DE; Grant, IS; Griffith, JAR; Honkanen, A; Huhta, M; Levins, JMG; Liukkonen, E; Oinonen, M; Pearson, MR; Penttila, H; Persson, B.L.; Richardson, DS; Tungate, G; Wheeler, P; Zybert, L; Aysto, J

    1997-01-01

    The standard Doppler-free technique of collinear laser spectroscopy has been successfully applied to radioisotopes from the ion-guide isotope separator (IGISOL) at the Universiry of Jyvaskyla. The laser resonance fluorescence signals for the Ba-140.142,Ba-144 radioisotopes show that the ion beam ene

  7. 2-PHOTON LASER SPECTROSCOPY OF THE MUONIUM 1S-2S TRANSITION

    NARCIS (Netherlands)

    Jungmann, Klaus-Peter; Baird, Patrick E.G.; Barr, John R.M.; Bressler, Christian; Curley, P.F.; Dixson, Ron; Eaton, Gordon H.; Ferguson, Alister I.; Geerds, Hans; Hughes, Vernon W.; Kenntner, Joachim; Lea, Steven N.; Maas, Frank; Persaud, Michael A.; zu Putlitz, Gisbert; Sandards, Patrick G.H.; Schwarz, Willi; Toner, William T.; Towrie, Michael; Woodman, George; Zhang, Li; Zhang, Zhizhang

    1991-01-01

    The 1(2) S 1/2 (F = 1) - 2(2) S 1/2 (F = 1) energy interval in muonium has been investigated by Doppler-free two-photon laser spectroscopy. The transition was observed by uniquely identifying and counting the muons released after the photoionization of the 2 S state by the same laser field. The meas

  8. The Self-Injected Laser for Picosecond Time-Resolved Spectroscopy

    OpenAIRE

    Armani, F.; Martini, F; Mataloni, P.

    1983-01-01

    The principles of operation and the characteristics of the self-injected picosecond laser are presented. We show that in spite of its simple design our device is able to generate very high power pulses in the picosecond domain. This warrants the use of this laser for time resolved spectroscopy in the picosecond domain.

  9. Deformation change in light iridium nuclei from laser spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Verney, D.; Le Blanc, F.; Obert, J.; Oms, J.; Puteaux, J.C.; Roussiere, B.; Sauvage, J. [IN2P3-CNRS/Universite Paris Sud-XI, Institut de Physique Nucleaire, Orsay Cedex (France); Cabaret, L.; Duong, H.T.; Pinard, J. [CNRS, Laboratoire Aime Cotton, Orsay Cedex (France); Crawford, J.E.; Lee, J.K.P. [McGill University, Physics Department, Montreal (Canada); Fricke, B.; Rashid, K. [Institut fuer Theoretische Physik der Universitaet Kassel, Kassel (Germany); Genevey, J.; Ibrahim, F. [IN2P3-CNRS/Universite Joseph Fourier-Grenoble I, Laboratoire de Physique Subatomique et de Cosmologie, Grenoble Cedex (France); Huber, G.; Krieg, M.; Sebastian, V. [Institut fuer Physik der Universitaet Mainz, Mainz (Germany); Le Scornet, G.; Lunney, D. [IN2P3-CNRS/Universite Paris Sud-XI, Centre de Spectrometrie Nucleaire et de Spectrometrie de Masse, Orsay Cedex (France)

    2006-12-15

    Laser spectroscopy measurements have been performed on neutron-deficient and stable Ir isotopes using the COMPLIS experimental setup installed at ISOLDE-CERN. The radioactive Ir atoms were obtained from successive decays of a mass-separated Hg beam deposited onto a carbon substrate after deceleration to 1kV and subsequently laser desorbed. A three-color, two-step resonant scheme was used to selectively ionize the desorbed Ir atoms. The hyperfine structure (HFS) and isotope shift (IS) of the first transition of the ionization path 5d{sup 7}6s{sup 24}F{sub 9/2}{yields}5d{sup 7}6s6p{sup 6}F{sub 11/2} at 351.5nm were measured for {sup 182-189}Ir, {sup 186}Ir{sup m} and the stable {sup 191,193}Ir. The nuclear magnetic moments {mu}{sub I} and the spectroscopic quadrupole moments Q{sub s} were obtained from the HFS spectra and the change of the mean square charge radii from the IS measurements. The sign of {mu}{sub I} was experimentally determined for the first time for the masses 182{<=}A{<=}189 and the isomeric state {sup 186}Ir{sup m}. The spectroscopic quadrupole moments of {sup 182}Ir and {sup 183}Ir were measured also for the first time. A large mean square charge radius change between {sup 187}Ir and {sup 186}Ir{sup g} and between {sup 186}Ir{sup m} and {sup 186}Ir{sup g} was observed corresponding to a sudden increase in deformation: from {beta}{sub 2}{approx_equal}+0.16 for the heavier group A = 193, 191, 189, 187 and 186m to {beta}{sub 2}{>=}+0.2 for the lighter group A=186g, 185, 184, 183 and 182. These results were analyzed in the framework of a microscopic treatment of an axial rotor plus one or two quasiparticle(s). This sudden deformation change is associated with a change in the proton state that describes the odd-nuclei ground state or that participates in the coupling with the neutron in the odd-odd nuclei. This state is identified with the {pi}3/2 {sup +}[402 ] orbital for the heavier group and with the {pi}1/2{sup -}[541 ] orbital stemming from the 1h

  10. Nanoparticle detection in aqueous solutions using Raman and Laser Induced Breakdown Spectroscopy

    NARCIS (Netherlands)

    Sovago, M.; Buis, E.-J.; Sandtke, M.

    2013-01-01

    We show the chemical identification and quantification of the concentration and size of nanoparticle (NP) dispersions in aqueous solutions by using a combination of Raman Spectroscopy and Laser Induced Breakdown Spectroscopy (LIBS). The two spectroscopic techniques are applied to demonstrate the NP

  11. Nanoparticle detection in aqueous solutions using Raman and Laser Induced Breakdown Spectroscopy

    NARCIS (Netherlands)

    Sovago, M.; Buis, E.-J.; Sandtke, M.

    2013-01-01

    We show the chemical identification and quantification of the concentration and size of nanoparticle (NP) dispersions in aqueous solutions by using a combination of Raman Spectroscopy and Laser Induced Breakdown Spectroscopy (LIBS). The two spectroscopic techniques are applied to demonstrate the NP

  12. Actively controlled tuning of an external cavity diode laser by polarization spectroscopy.

    Science.gov (United States)

    Führer, Thorsten; Stang, Denise; Walther, Thomas

    2009-03-30

    We report on an universal method to achieve and sustain a large mode-hop free tuning range of an external cavity diode laser. By locking one of the resonators using a closed loop control based on polarization spectroscopy while tuning the laser we achieved mode-hop free tuning of up to 130 GHz with a non AR-coated, off-the-shelf laser diode.

  13. Methanogenic activity tests by Infrared Tunable Diode Laser Absorption Spectroscopy.

    Science.gov (United States)

    Martinez-Cruz, Karla; Sepulveda-Jauregui, Armando; Escobar-Orozco, Nayeli; Thalasso, Frederic

    2012-10-01

    Methanogenic activity (MA) tests are commonly carried out to estimate the capability of anaerobic biomass to treat effluents, to evaluate anaerobic activity in bioreactors or natural ecosystems, or to quantify inhibitory effects on methanogenic activity. These activity tests are usually based on the measurement of the volume of biogas produced by volumetric, pressure increase or gas chromatography (GC) methods. In this study, we present an alternative method for non-invasive measurement of methane produced during activity tests in closed vials, based on Infrared Tunable Diode Laser Absorption Spectroscopy (MA-TDLAS). This new method was tested during model acetoclastic and hydrogenotrophic methanogenic activity tests and was compared to a more traditional method based on gas chromatography. From the results obtained, the CH(4) detection limit of the method was estimated to 60 ppm and the minimum measurable methane production rate was estimated to 1.09(.)10(-3) mg l(-1) h(-1), which is below CH(4) production rate usually reported in both anaerobic reactors and natural ecosystems. Additionally to sensitivity, the method has several potential interests compared to more traditional methods among which short measurements time allowing the measurement of a large number of MA test vials, non-invasive measurements avoiding leakage or external interferences and similar cost to GC based methods. It is concluded that MA-TDLAS is a promising method that could be of interest not only in the field of anaerobic digestion but also, in the field of environmental ecology where CH(4) production rates are usually very low. Copyright © 2012 Elsevier B.V. All rights reserved.

  14. Independent component analysis classification of laser induced breakdown spectroscopy spectra

    Energy Technology Data Exchange (ETDEWEB)

    Forni, Olivier, E-mail: olivier.forni@irap.omp.eu [Université de Toulouse, UPS-OMP, Institut de Recherche en Astrophysiqe et Planétologie, Toulouse (France); CNRS, IRAP, 9, av. Colonel Roche, BP 44346, F-31028 Cedex 4, Toulouse (France); Maurice, Sylvestre, E-mail: sylvestre.maurice@irap.omp.eu [Université de Toulouse, UPS-OMP, Institut de Recherche en Astrophysiqe et Planétologie, Toulouse (France); CNRS, IRAP, 9, av. Colonel Roche, BP 44346, F-31028 Cedex 4, Toulouse (France); Gasnault, Olivier, E-mail: olivier.gasnault@irap.omp.eu [Université de Toulouse, UPS-OMP, Institut de Recherche en Astrophysiqe et Planétologie, Toulouse (France); CNRS, IRAP, 9, av. Colonel Roche, BP 44346, F-31028 Cedex 4, Toulouse (France); Wiens, Roger C., E-mail: rwiens@lanl.gov [Space Remote Sensing, Los Alamos National Laboratory, Los Alamos, NM 87544 (United States); Cousin, Agnès, E-mail: acousin@lanl.gov [Université de Toulouse, UPS-OMP, Institut de Recherche en Astrophysiqe et Planétologie, Toulouse (France); CNRS, IRAP, 9, av. Colonel Roche, BP 44346, F-31028 Cedex 4, Toulouse (France); Chemical Division, Los Alamos National Laboratory, Los Alamos, NM 87544 (United States); Clegg, Samuel M., E-mail: sclegg@lanl.gov [Chemical Division, Los Alamos National Laboratory, Los Alamos, NM 87544 (United States); Sirven, Jean-Baptiste, E-mail: jean-baptiste.sirven@cea.f [CEA Saclay, DEN/DPC/SCP, 91191 Cedex, Gif sur Yvette (France); Lasue, Jérémie, E-mail: jeremie.lasue@irap.omp.eu [Université de Toulouse, UPS-OMP, Institut de Recherche en Astrophysiqe et Planétologie, Toulouse (France); CNRS, IRAP, 9, av. Colonel Roche, BP 44346, F-31028 Cedex 4, Toulouse (France)

    2013-08-01

    The ChemCam instrument on board Mars Science Laboratory (MSL) rover uses the laser-induced breakdown spectroscopy (LIBS) technique to remotely analyze Martian rocks. It retrieves spectra up to a distance of seven meters to quantify and to quantitatively analyze the sampled rocks. Like any field application, on-site measurements by LIBS are altered by diverse matrix effects which induce signal variations that are specific to the nature of the sample. Qualitative aspects remain to be studied, particularly LIBS sample identification to determine which samples are of interest for further analysis by ChemCam and other rover instruments. This can be performed with the help of different chemometric methods that model the spectra variance in order to identify a the rock from its spectrum. In this paper we test independent components analysis (ICA) rock classification by remote LIBS. We show that using measures of distance in ICA space, namely the Manhattan and the Mahalanobis distance, we can efficiently classify spectra of an unknown rock. The Mahalanobis distance gives overall better performances and is easier to manage than the Manhattan distance for which the determination of the cut-off distance is not easy. However these two techniques are complementary and their analytical performances will improve with time during MSL operations as the quantity of available Martian spectra will grow. The analysis accuracy and performances will benefit from a combination of the two approaches. - Highlights: • We use a novel independent component analysis method to classify LIBS spectra. • We demonstrate the usefulness of ICA. • We report the performances of the ICA classification. • We compare it to other classical classification schemes.

  15. Laser Desorption Supersonic Jet Spectroscopy of Hydrated Tyrosine

    Science.gov (United States)

    Oba, Hikari; Shimozono, Yoko; Ishiuchi, Shun-Ichi; Fujii, Masaaki; Carcabal, Pierre

    2013-06-01

    The structure of tyrosine (tyr) consists of amino-acid chain and phenol, and it has roughly two possible binding sites for water, amino-acid site and phenolic OH site. Investigating how water molecule binds to tyr will give fundamental information for hydrations of peptide and protein. Resonance enhanced multi photon ionization (REMPI) spectrum of tyr-water 1:1 cluster has already been reported by de Vries and co-workers, however, no analysis on the hydrated structures has been reported. In the REMPI spectrum, two clusters of bands are observed; one appears at ˜35600 cm^{-1} energy region which is the almost same with 0-0 transitions of tyr monomer, and another is observed at ˜300 cm^{-1} lower than the former. Based on the electronic transition energy of phenylalanine and the hydrated clusters, the former is expected to be derived from a structure that water binds to amino acid site. On the other hand, it is plausibly predicted that the latter originates from a structure that water binds to phenolic OH group, because the electronic transition of mono hydrated phenol is ˜300 cm^{-1} red-shifted from the monomer. We applied IR dip spectroscopy which can measure conformer selective IR spectra to the tyr-(H_{2}O)_{1} clusters by using laser desorption supersonic jet technique to confirm the assignments. Especially in the phenolic OH bound isomer, it was found that the intra molecular hydrogen bond within amino-acid chain, which is far from the water molecule and cannot interact directly with each other, is strengthened by the hydration. A. Abio-Riziq et al., J. Phys. Chem. A, 115, 6077 (2011). Y. Shimozono, et al., Phys. Chem. Chem. Phys., (2013) DOI: 10.1039/c3cp43573c. T. Ebata et al., Phys. Chem. Chem. Phys., 8, 4783 (2006). T. Watanabe et al., J. Chem. Phys., 105, 408 (1996).

  16. High-sensitivity time-resolved intracavity laser Fourier transform spectroscopy with vertical cavity surface emitting multiple quantum well lasers

    CERN Document Server

    Picqué, N; Kachanov, A A; Picqu\\'e, Nathalie; Guelachvili, Guy; Kachanov, Alexander A.

    2003-01-01

    Spectra comprised of hundreds of time-components for absorption path lengths up to 130 km have been recorded around 1050 nm by combining two recent techniques, intracavity laser spectroscopy with vertical external cavity surface emitting multiple-quantum-well lasers and time-resolved Fourier transform spectroscopy. A sensitivity of 1 10^{-10} cm^{-1}.Hz^{-1/2} is achieved, for simultaneously acquired 10^4 spectral elements, three orders of magnitude better than the sensitivity obtained in previous similar experiments. Specific advantages of the method, especially for frequency and intensity metrology of weak absorption transitions, are discussed.

  17. Recovery of acetylene absorption line profile basing on tunable diode laser spectroscopy with intensity modulation and photoacoustic spectroscopy

    Science.gov (United States)

    Li, Li; Thursby, Graham; Stewart, George; Arsad, Norhana; Uttamchandani, Deepak; Culshaw, Brian; Wang, Yiding

    2010-04-01

    A novel and direct absorption line recovery technique based on tunable diode laser spectroscopy with intensity modulation is presented. Photoacoustic spectroscopy is applied for high sensitivity, zero background and efficient acoustic enhancement at a low modulation frequency. A micro-electromechanical systems (MEMS) mirror driven by an electrothermal actuator is used for generating laser intensity modulation (without wavelength modulation) through the external reflection. The MEMS mirror with 10μm thick structure material layer and 100nm thick gold coating is formed as a circular mirror of 2mm diameter attached to an electrothermal actuator and is fabricated on a chip that is wire-bonded and placed on a PCB holder. Low modulation frequency is adopted (since the resonant frequencies of the photoacoustic gas cell and the electrothermal actuator are different) and intrinsic high signal amplitude characteristics in low frequency region achieved from measured frequency responses for the MEMS mirror and the gas cell. Based on the property of photoacoustic spectroscopy and Beer's law that detectable sensitivity is a function of input laser intensity in the case of constant gas concentration and laser path length, a Keopsys erbium doped fibre amplifier (EDFA) with opto-communication C band and high output power up to 1W is chosen to increase the laser power. High modulation depth is achieved through adjusting the MEMS mirror's reflection position and driving voltage. In order to scan through the target gas absorption line, the temperature swept method is adopted for the tunable distributed feed-back (DFB) diode laser working at 1535nm that accesses the near-infrared vibration-rotation spectrum of acetylene. The profile of acetylene P17 absorption line at 1535.39nm is recovered ideally for ~100 parts-per-million (ppm) acetylene balanced by nitrogen. The experimental signal to noise ratio (SNR) of absorption line recovery for 500mW laser power was ~80 and hence the

  18. Laser-induced breakdown spectroscopy detection of heavy metal in water based on graphite conch method

    Science.gov (United States)

    Wang, Chunlong; Liu, Jianguo; Zhao, Nanjing; Shi, Huan; Liu, Lituo; Ma, Mingjun; Zhang, Wei; Chen, Dong; Liu, Jing; Zhang, Yujun; Liu, Wenqing

    2012-10-01

    The laser-induced breakdown spectroscopy emission characteristics of trace heavy metal lead in water is studied based on graphite conch method, with a 1064nm wavelength Nd: YAG laser as excitation source, the echelle spectrometer and ICCD detector are used for spectral separation and high sensitive detection with high resolution and wide spectral range. The delay time 900ns and gate time 1600ns are determined in the experiment. The calibration curve of Pb is plotted based on the different concentration measurement results, and a limit of detection of 0.0138mg / L is obtained for Pb in water. Graphite conch method effectively overcomes the current problems on laser-induced breakdown spectroscopy detection of heavy metal in water. The detection limits and stability are improved. The reference data is provided for further study on the fast measurement of trace heavy metals in water by laser induced breakdown spectroscopy technique.

  19. Low-temperature micro-photoluminescence spectroscopy on laser-doped silicon with different surface conditions

    Science.gov (United States)

    Han, Young-Joon; Franklin, Evan; Fell, Andreas; Ernst, Marco; Nguyen, Hieu T.; Macdonald, Daniel

    2016-04-01

    Low-temperature micro-photoluminescence spectroscopy (μ-PLS) is applied to investigate shallow layers of laser-processed silicon for solar cell applications. Micron-scale measurement (with spatial resolution down to 1 μm) enables investigation of the fundamental impact of laser processing on the electronic properties of silicon as a function of position within the laser-processed region, and in particular at specific positions such as at the boundary/edge of processed and unprocessed regions. Low-temperature μ-PLS enables qualitative analysis of laser-processed regions by identifying PLS signals corresponding to both laser-induced doping and laser-induced damage. We show that the position of particular luminescence peaks can be attributed to band-gap narrowing corresponding to different levels of subsurface laser doping, which is achieved via multiple 248 nm nanosecond excimer laser pulses with fluences in the range 1.5-4 J/cm2 and using commercially available boron-rich spin-on-dopant precursor films. We demonstrate that characteristic defect PL spectra can be observed subsequent to laser doping, providing evidence of laser-induced crystal damage. The impact of laser parameters such as fluence and number of repeat pulses on laser-induced damage is also analyzed by observing the relative level of defect PL spectra and absolute luminescence intensity. Luminescence owing to laser-induced damage is observed to be considerably larger at the boundaries of laser-doped regions than at the centers, highlighting the significant role of the edges of laser-doped region on laser doping quality. Furthermore, by comparing the damage signal observed after laser processing of two different substrate surface conditions (chemically-mechanically polished and tetramethylammonium hydroxide etched), we show that wafer preparation can be an important factor impacting the quality of laser-processed silicon and solar cells.

  20. On-line identification of lysergic acid diethylamide (LSD) in tablets using a combination of a sweeping technique and micellar electrokinetic chromatography/77 K fluorescence spectroscopy.

    Science.gov (United States)

    Fang, Ching; Liu, Ju-Tsung; Lin, Cheng-Huang

    2003-03-01

    This work describes a novel method for the accurate determination of lysergic acid diethylamide (LSD) in tablets. A technique involving sweeping-micellar electrokinetic chromatography (MEKC) was used for the initial on-line concentration and separation, after which a cryogenic molecular fluorescence experiment was performed at 77 K. Using this approach, not only the separation of LSD from the tablet extract was achieved, but on-line spectra were readily distinguishable and could be unambiguously assigned. The results are in agreement with analyses by gas chromatography-mass spectrometry (GC-MS). Thus, this method, which was found to be accurate, sensitive and rapid, has the potential for use as a reliable complementary method to GC-MS in such analyses.

  1. A Laser System for the Spectroscopy of Highly-Charged Bismuth Ions

    CERN Document Server

    Albrecht, S; Siegel, C; Herschbach, N; Birkl, G

    2011-01-01

    We present and characterize a laser system for the spectroscopy on highly-charged ^209Bi^82+ ions at a wavelength of 243.87 nm. For absolute frequency stabilization, the laser system is locked to a near-infra-red laser stabilized to a rubidium transition line using a transfer cavity based locking scheme. Tuning of the output frequency with high precision is achieved via a tunable rf offset lock. A sample-and-hold technique gives an extended tuning range of several THz in the UV. This scheme is universally applicable to the stabilization of laser systems at wavelengths not directly accessible to atomic or molecular resonances. We determine the frequency accuracy of the laser system using Doppler-free absorption spectroscopy of Te_2 vapour at 488 nm. Scaled to the target wavelength of 244 nm, we achieve a frequency uncertainty of \\sigma_{244nm} = 6.14 MHz (one standard deviation) over six days of operation.

  2. Laser Spectroscopy Based Multi-Gas Monitor Technology Demonstration

    Science.gov (United States)

    Mudgett, Paul D.; Pilgrim, Jeffrey S.

    2016-01-01

    The timing was right in the “evolution” of low power tunable diode laser spectroscopy (TDLS) to design a spacecraft cabin air monitor around technology being developed at a small company funded by SBIR grants. NASA Centers had been monitoring their progress hoping that certain key gaps in the long term gas monitoring development roadmap could be filled by TDLS. The first iteration of a monitor for multiple gases called the Multi-Gas Monitor (MGM) which measures oxygen, carbon dioxide, ammonia and water vapor, as well as temperature and pressure. In January 2013, the ISS Program being particularly interested in ammonia funded a technology demonstration of MGM. The project was a joint effort between Vista Photonics for the sensor, NASA-JSC for project management and laboratory calibration, and Nanoracks for the enclosure and payload certification/integration. Nanoracks was selected in order to use their new experimental infrastructure located in an EXPRESS rack in the JEM. The MGM enclosure has multiple power supply options including 5VDC USB interface to the Nanoracks Frame, 28VDC Express Rack power and internal rechargeable batteries. MGM was calibrated at NASA-JSC in July 2013, delivered to ISS on 37 Soyuz in November 2013 and was installed and activated in February 2014. MGM resided in the Nanoracks Frame making continuous measurements the majority of the time, but also spent a day in Node 3 on battery power, and a month in the US Lab Module on 28VDC power, as part of the demonstration. Data was downloaded via Nanoracks on roughly a weekly basis. Comparisons were made with data from the Major Constituents Analyzer (MCA) which draws and analyzes air from JEM and other modules several times per hour. A crewmember challenged the carbon dioxide channel by breathing into the intake upon startup, and challenged the ammonia channel later using a commercial ammonia inhalant. Many interesting phenomena in the cabin atmosphere were detected during the tech demo

  3. Optical-fiber-based laser-induced breakdown spectroscopy for detection of early caries

    Science.gov (United States)

    Sasazawa, Shuhei; Kakino, Satoko; Matsuura, Yuji

    2015-06-01

    A laser-induced breakdown spectroscopy (LIBS) system targeting for the in vivo analysis of tooth enamel is described. The system is planned to enable real-time analysis of teeth during laser dental treatment by utilizing a hollow optical fiber that transmits both Q-switched Nd:YAG laser light for LIBS and infrared Er:YAG laser light for tooth ablation. The sensitivity of caries detection was substantially improved by expanding the spectral region under analysis to ultraviolet (UV) light and by focusing on emission peaks of Zn in the UV region. Subsequently, early caries were distinguished from healthy teeth with accuracy rates above 80% in vitro.

  4. Optical-fiber-based laser-induced breakdown spectroscopy for detection of early caries.

    Science.gov (United States)

    Sasazawa, Shuhei; Kakino, Satoko; Matsuura, Yuji

    2015-06-01

    A laser-induced breakdown spectroscopy (LIBS) system targeting for the in vivo analysis of tooth enamel is described. The system is planned to enable real-time analysis of teeth during laser dental treatment by utilizing a hollow optical fiber that transmits both Q-switched Nd:YAG laser light for LIBS and infrared Er:YAG laser light for tooth ablation. The sensitivity of caries detection was substantially improved by expanding the spectral region under analysis to ultraviolet (UV) light and by focusing on emission peaks of Zn in the UV region. Subsequently, early caries were distinguished from healthy teeth with accuracy rates above 80% in vitro.

  5. Metastable Magnesium fluorescence spectroscopy using a frequency-stabilized 517 nm laser

    DEFF Research Database (Denmark)

    He, Ming; Jensen, Brian B; Therkildsen, Kasper T

    2009-01-01

    We present a laser operating at 517 nm for our Magnesium laser-cooling and atomic clock project. A two-stage Yb-doped fiber amplifier (YDFA) system generates more than 1.5 W of 1034 nm light when seeded with a 15 mW diode laser. Using a periodically poled lithium niobate (PPLN) waveguide, we...... obtained more than 40 mW of 517 nm output power by single pass frequency doubling. In addition, fluorescence spectroscopy of metastable magnesium atoms could be used to stabilize the 517 nm laser to an absolute frequency within 1 MHz....

  6. Investigation of Normalization Methods using Plasma Parameters for Laser Induced Breakdown Spectroscopy (LIBS) under simulated Martian Conditions

    OpenAIRE

    Vogt, David; Schröder, Susanne; Hübers, H.-W.

    2017-01-01

    Laser Induced Breakdown Spectroscopy data need to be normalized, especially in the field of planetary exploration We investigated plasma parameters as temperature and electron density for this purpose.

  7. Comparing predictive ability of Laser-Induced Breakdown Spectroscopy to Near Infrared Spectroscopy for soil texture and organic carbon determination

    DEFF Research Database (Denmark)

    Knadel, Maria; Peng, Yi; Gislum, René;

    and texture was tested and compared with near infrared spectroscopy (NIRS) technique and traditional laboratory analysis. Calibration models were developed on 50 topsoil samples. For all properties except silt, higher predictive ability of LIBS than NIRS models was obtained. Successful calibrations indicate......Soil organic carbon (SOC) and texture have a practical value for agronomy and the environment. Thus, alternative techniques to supplement or substitute for the expensive conventional analysis of soil are developed. Here the feasibility of laser-induced breakdown spectroscopy (LIBS) to determine SOC...

  8. Measurement of OH reactivity by laser flash photolysis coupled with laser-induced fluorescence spectroscopy

    Science.gov (United States)

    Stone, Daniel; Whalley, Lisa K.; Ingham, Trevor; Edwards, Peter M.; Cryer, Danny R.; Brumby, Charlotte A.; Seakins, Paul W.; Heard, Dwayne E.

    2016-07-01

    OH reactivity (k'OH) is the total pseudo-first-order loss rate coefficient describing the removal of OH radicals to all sinks in the atmosphere, and is the inverse of the chemical lifetime of OH. Measurements of ambient OH reactivity can be used to discover the extent to which measured OH sinks contribute to the total OH loss rate. Thus, OH reactivity measurements enable determination of the comprehensiveness of measurements used in models to predict air quality and ozone production, and, in conjunction with measurements of OH radical concentrations, to assess our understanding of OH production rates. In this work, we describe the design and characterisation of an instrument to measure OH reactivity using laser flash photolysis coupled to laser-induced fluorescence (LFP-LIF) spectroscopy. The LFP-LIF technique produces OH radicals in isolation, and thus minimises potential interferences in OH reactivity measurements owing to the reaction of HO2 with NO which can occur if HO2 is co-produced with OH in the instrument. Capabilities of the instrument for ambient OH reactivity measurements are illustrated by data collected during field campaigns in London, UK, and York, UK. The instrumental limit of detection for k'OH was determined to be 1.0 s-1 for the campaign in London and 0.4 s-1 for the campaign in York. The precision, determined by laboratory experiment, is typically < 1 s-1 for most ambient measurements of OH reactivity. Total uncertainty in ambient measurements of OH reactivity is ˜ 6 %. We also present the coupling and characterisation of the LFP-LIF instrument to an atmospheric chamber for measurements of OH reactivity during simulated experiments, and provide suggestions for future improvements to OH reactivity LFP-LIF instruments.

  9. [Research Progress on Laser-Induced Breakdown Spectroscopy Based on Resonance Excitation].

    Science.gov (United States)

    Wang, Xu-zhao; Hao, Zhong-qi; Guo, Lian-bo; Li, Xiang-you; Lu, Yong-feng; Zeng, Xiao-yan

    2015-05-01

    Laser-induced breakdown spectroscopy (LIBS), a new kind of atomic spectrum analysis technology, has attracted much atterition of the researchers due to its characteristics of real-time, simultaneous multi-element analysis, and no sample preparation. However, the poor analytical sensitivity has been an important factor that restricts the development of this technology. LIBS based on resonance excitation combines atomic fluorescence spectroscopy and laser-induced breakdown spectroscopy and selectively excites the target elements. In this way, the analytical sensitivity of LIBS can be improved substantially and its application for trace elements detection is greatly expanded. In this paper, the research development of LIBS based on resonance excitation is summarized. The generation of atomic, fluorescence spectrum in laser-induced plasma, the typical classification and the basic principle of LIBS based on resonance. excitation are introduced. The influence of ablation laser energy, resonant laser energy and wavelength, delay between the ablation laser and the resonant laser, and the gate width on spectral enhancement are analyzed in detail. The application status and deficiencies of LIBS based on resonance excitation in the fields of metallurgy, environmental monitoring and isotope detection are elaborated. Future prospects of LIBS based on resonance excitation are also described.

  10. A narrow-band injection-seeded pulsed titanium : sapphire oscillator-amplifier system with on-line chirp analysis for high-resolution spectroscopy

    NARCIS (Netherlands)

    Hannemann, S.; Duijn, van E.J.; Ubachs, W.M.G.

    2007-01-01

    A narrow-band tunable injection-seeded pulsed titanium:sapphire laser system has been developed for application in high-resolution spectroscopic studies at the fundamental wavelengths in the near infrared as well as in the ultraviolet, deep ultraviolet, and extreme ultraviolet after upconversion.

  11. A narrow-band injection-seeded pulsed titanium : sapphire oscillator-amplifier system with on-line chirp analysis for high-resolution spectroscopy

    NARCIS (Netherlands)

    Hannemann, S.; Duijn, van E.J.; Ubachs, W.M.G.

    2007-01-01

    A narrow-band tunable injection-seeded pulsed titanium:sapphire laser system has been developed for application in high-resolution spectroscopic studies at the fundamental wavelengths in the near infrared as well as in the ultraviolet, deep ultraviolet, and extreme ultraviolet after upconversion. Sp

  12. Analysis of plutonium oxide surrogate residue using laser-induced breakdown spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Zheng Hongbo [Department of Applied Physics, College of Science, Nanjing University of Technology, Nanjing (China); Yueh, F.Y.; Miller, Tracy [Institute for Clean Energy Technology (ICET), Mississippi State University, Starkville, MS 39759-7704 (United States); Singh, Jagdish P. [Institute for Clean Energy Technology (ICET), Mississippi State University, Starkville, MS 39759-7704 (United States)], E-mail: singh@icet.msstate.edu; Zeigler, Kristine E.; Marra, James C. [Savannah River National Laboratory (SRNL), Aiken, SC 29808 (United States)

    2008-09-15

    Laser-induced breakdown spectroscopy was used to determine the elemental composition of a CeO{sub 2} composite powder for process control verification during lanthanide borosilicate glass fabrication. Cerium oxide is used as a surrogate for plutonium oxide, which along with other canister contents will be combined with frit to make glass. Laser-induced breakdown spectroscopy data for the composition of the CeO{sub 2} batch containing concentrations of Ce, Cr, Si, Fe, Ta, Ni, Zn, Al Mg, Gd, and W were quantitatively determined from laser-induced breakdown spectroscopy spectra of both pellet and powder samples. The results of both forms were compared and it was determined that the pellet data gave slightly better precision than the powder sample.

  13. Wideband laser locking to an atomic reference with modulation transfer spectroscopy.

    Science.gov (United States)

    Negnevitsky, V; Turner, L D

    2013-02-11

    We demonstrate that conventional modulated spectroscopy apparatus, used for laser frequency stabilization in many atomic physics laboratories, can be enhanced to provide a wideband lock delivering deep suppression of frequency noise across the acoustic range. Using an acousto-optic modulator driven with an agile oscillator, we show that wideband frequency modulation of the pump laser in modulation transfer spectroscopy produces the unique single lock-point spectrum previously demonstrated with electro-optic phase modulation. We achieve a laser lock with 100 kHz feedback bandwidth, limited by our laser control electronics. This bandwidth is sufficient to reduce frequency noise by 30 dB across the acoustic range and narrows the imputed linewidth by a factor of five.

  14. Simultaneous laser induced breakdown spectroscopy and Pd-assisted methane decomposition at different pressures

    Energy Technology Data Exchange (ETDEWEB)

    Reyhani, A. [Phys. Dept., Faculty of Science, Imam Khomeini International University, Qazvin, 34149-16818 (Iran, Islamic Republic of); Mortazavi, S.Z. [Phys. Dept., Amirkabir University of Technology, P.O. Box 15875-4413, Tehran (Iran, Islamic Republic of); Parvin, P., E-mail: parvin@aut.ac.ir [Phys. Dept., Amirkabir University of Technology, P.O. Box 15875-4413, Tehran (Iran, Islamic Republic of); Mahmoudi, Z. [Phys. Dept., Amirkabir University of Technology, P.O. Box 15875-4413, Tehran (Iran, Islamic Republic of)

    2012-08-15

    Methane decomposition is investigated during Pd-assisted laser induced plasma in the controlled chamber at various pressures using Q-switched Nd:YAG laser. Real time LIBS monitoring is applied to reveal the involved mechanisms during methane decomposition by inspecting the plasma parameters at mano-metric pressures of 1 to 10 mbar. The dependence of electron density and plasma temperature with pressure is also studied. It is shown that the plasma recreates higher hydrocarbons during the decomposition of methane. In addition, Fourier transform infrared spectroscopy, gas chromatography, scanning electron microscopy and transmission electron microscopy are applied to support the findings. - Highlights: Black-Right-Pointing-Pointer Simultaneous laser induced breakdown spectroscopy Black-Right-Pointing-Pointer Pd-assisted methane decomposition Black-Right-Pointing-Pointer Nanosecond pulsed laser decomposition of methane Black-Right-Pointing-Pointer Generation of higher hydrocarbon Black-Right-Pointing-Pointer Dependence of electron density and temperature of induced plasma with pressure.

  15. An all-solid state laser system for the laser ion sources RILIS and in-source laser spectroscopy of astatine at ISOLDE/CERN

    Energy Technology Data Exchange (ETDEWEB)

    Rothe, Sebastian

    2012-09-24

    This doctoral thesis describes the extension of the resonance ionization laser ion source RILIS at CERN/ISOLDE by the addition of an all-solid state tunable titanium:sapphire (Ti:Sa) laser system to complement the well-established system of dye lasers. Synchronous operation of the so called Dual RILIS system of Ti:Sa and dye lasers was investigated and the potential for increased ion beam intensity, reliability, and reduced setup time has been demonstrated. In-source resonance ionization spectroscopy was performed at ISOLDE/CERN and at ISAC/TRIUMF radioactive ion beam facilities to develop an efficient and selective three-colour ionization scheme for the purely radioactive element astatine. A LabVIEW based monitoring, control and measurement system was conceived which enabled, in conjunction with Dual RILIS operation, the spectroscopy of high lying Rydberg states, from which the ionization potential of the astatine atom was determined for the first time experimentally.

  16. An all-solid state laser system for the laser ion source RILIS and in-source laser spectroscopy of astatine at ISOLDE, CERN

    CERN Document Server

    Rothe, Sebastian; Nörtershäuser, W

    This doctoral thesis describes the extension of the resonance ionization laser ion source RILIS at ISOLDE, CERN, by the addition of an all-solid state tuneable titanium: sapphire (Ti:Sa) laser system to complement the well-established system of dye lasers. Synchronous operation of the so called Dual RILIS system of Ti:Sa and dye lasers was investigated and the potential for increased ion beam intensity, reliability, and reduced setup time has been demonstrated. In-source resonance ionization spectroscopy was performed at ISOLDE, CERN, and at ISAC, TRIUMF, radioactive ion beam facilities to develop an efficient and selective three-colour ionization scheme for the purely radioactive element astatine. A LabVIEW based monitoring, control and measurement system was conceived which enabled, in conjunction with Dual RILIS operation, the spectroscopy of high lying Rydberg states, from which the ionization potential of the astatine atom was determined for the first time experimentally.

  17. Note: A novel technique for analysis of aqueous solutions by laser-induced breakdown spectroscopy.

    Science.gov (United States)

    Rusak, D A; Anthony, T P; Bell, Z T

    2015-11-01

    Surface-enhanced Raman spectroscopy (SERS) substrates typically consist of gold or silver nanoparticles deposited on a non-conductive substrate. In Raman spectroscopy, the nanoparticles produce an enhancement of the electromagnetic field which, in turn, leads to greater electronic excitation of molecules in the local environment. Here, we show that these same surfaces can be used to enhance the signal-to-noise ratio obtained in laser-induced breakdown spectroscopy of aqueous solutions. In this case, the SERS substrates not only lower breakdown thresholds and lead to more efficient plasma initiation but also provide an appropriately wettable surface for the deposition of the liquid. We refer to this technique as surface-enhanced laser-induced breakdown spectroscopy.

  18. Laser sources and techniques for spectroscopy and dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Kung, A.H. [Lawrence Berkeley Laboratory, CA (United States)

    1993-12-01

    This program focuses on the development of novel laser and spectroscopic techniques in the IR, UV, and VUV regions for studying combustion related molecular dynamics at the microscopic level. Laser spectroscopic techniques have proven to be extremely powerful in the investigation of molecular processes which require very high sensitivity and selectivity. The authors approach is to use quantum electronic and non-linear optical techniques to extend the spectral coverage and to enhance the optical power of ultrahigh resolution laser sources so as to obtain and analyze photoionization, fluorescence, and photoelectron spectra of jet-cooled free radicals and of reaction products resulting from unimolecular and bimolecular dissociations. New spectroscopic techniques are developed with these sources for the detection of optically thin and often short-lived species. Recent activities center on regenerative amplification of high resolution solid-state lasers, development of tunable high power mid-IR lasers and short-pulse UV/VUV tunable lasers, and development of a multipurpose high-order suppressor crossed molecular beam apparatus for use with synchrotron radiation sources. This program also provides scientific and technical support within the Chemical Sciences Division to the development of LBL`s Combustion Dynamics Initiative.

  19. Ultrafast dynamic ellipsometry and spectroscopies of laser shocked materials

    Energy Technology Data Exchange (ETDEWEB)

    Mcgrane, Shawn David [Los Alamos National Laboratory; Bolme, Cindy B [Los Alamos National Laboratory; Whitley, Von H [Los Alamos National Laboratory; Moore, David S [Los Alamos National Laboratory

    2010-01-01

    Ultrafast ellipsometry and transient absorption spectroscopies are used to measure material dynamics under extreme conditions of temperature, pressure, and volumetric compression induced by shock wave loading with a chirped, spectrally clipped shock drive pulse.

  20. Cavity ringdown laser absorption spectroscopy detection of formyl (HCO) radical in a low pressure flame

    Science.gov (United States)

    Scherer, J. J.; Rakestraw, D. J.

    1997-01-01

    The formyl radical has been detected via the ÖX˜ system in a low pressure CH 4/N 2/O 2 flame using cavity ringdown laser absorption spectroscopy. The direct absorption data obtained in these initial studies allows determination of the absolute HCO concentration in the flame of ca. 2.1(±0.9) × 10 13 mol cm -3, which is in excellent agreement with flame chemistry simulations. The extrapolated detection limit at 300 K of ≈ 1.4(±0.6) × 10 11 mol cm -3 is comparable to that of other methods, including intracavity laser absorption spectroscopy.

  1. [Application of laser induced breakdown spectroscopy (LIBS) to microdetection of Au film machining].

    Science.gov (United States)

    Yuan, Dong-qing; Zhou, Ming; Shen, Jian; Ren, Nai-fei; Cai, Lan

    2008-10-01

    Film micro-machining is a core in micro- and nano- technology, micro-electro-mechanical systems and photoelectron field. However, it is difficult to control the quality of machining in processing film. In the present paper the authors propose a method to solve this problem by using laser induced breakdown spectroscopy (LIBS). The authors investigated the relation between excitation condition and the quantity of plasma in the process of micro-machining by pulse laser. At low frequency (machining become true.

  2. Development of a gated optical multichannel analyser for laser-plasma spectroscopy

    OpenAIRE

    Corcoran, Richard

    1990-01-01

    An Optical Multichannel Analyser (OMA) has been developed for the detection of radiation from laser-produced plasmas (LPPs). The system is based on a gated image - intensified photodiode array (PDA) Software for the control of, and data acquisition from, the OMA system has been developed. A high resolution (10ns) delay generator was also designed and constructed to permit timeresolved. optical spectroscopy. The system has been tested and operated with a laser plasma source m...

  3. Laser Optogalvanic Spectroscopy: Experimental Details and Potential Applications in R and D

    OpenAIRE

    M.N. Reddy

    1994-01-01

    Laser Optogalvanic Spectroscopy (LOGS) is an extremely sensitive detection technique based on the 'Optogalvanic Effect'. The impedance change of gaseous discharge following the absorption of resonant laser light by the discharge species has proved to be a powerful spectroscopic tool to investigate all kinds of matter in vapour phase in discharge plasmas and flames. LOGS does not require any optical detector and the signal-to-noise ratios are often greater than 10/sup 3/. The advent of...

  4. [Classification of results of studying blood plasma with laser correlation spectroscopy based on semiotics of preclinical and clinical states].

    Science.gov (United States)

    Ternovoĭ, K S; Kryzhanovskiĭ, G N; Musiĭchuk, Iu I; Noskin, L A; Klopov, N V; Noskin, V A; Starodub, N F

    1998-01-01

    The usage of laser correlation spectroscopy for verification of preclinical and clinical states is substantiated. Developed "semiotic" classifier for solving the problems of preclinical and clinical states is presented. The substantiation of biological algorithms as well as the mathematical support and software for the proposed classifier for the data of laser correlation spectroscopy of blood plasma are presented.

  5. The use of lasers for studying ultrahigh speed phenomena (picoseconds): equipement of a picosecond spectroscopy laboratory using synchronized mode lasers

    Energy Technology Data Exchange (ETDEWEB)

    Goujon, P.; Pochon, E.; Clerc, M. (CEA Centre d' Etudes Nucleaires de Saclay, 91 - Gif-sur-Yvette (France). Section des Recherches et de l' Interaction du Rayonnement avec la Matiere)

    1975-07-01

    The spectroscopy laboratory is equipped with a dye laser and a neodymium glass laser. Detection in one case is made by means of a streak picosecond camera capable of a 5 ps time interval. A second detection method uses a CS/sub 2/ Kerr cell switch based on the Duguay principle. The first qualitative results concerning the fluorescence of DODCI and chlorophyll in vivo as well as the bleaching and recovering of the absorption of the electron solvated in liquid ammonia, have shown that this equipment could effectively enable the observation of physical-chemical processes as brief as 5 ps. (FR)

  6. High-resolution mirror temperature mapping in GaN-based diode lasers by thermoreflectance spectroscopy

    Science.gov (United States)

    Pierścińska, Dorota; Marona, Łucja; Pierściński, Kamil; Wiśniewski, Przemysław; Perlin, Piotr; Bugajski, Maciej

    2017-02-01

    In this paper accurate measurements of temperature distribution on the facet of GaN-based diode lasers are presented as well as development of the instrumentation for high-resolution thermal imaging based on thermoreflectance. It is shown that thermoreflectance can be successfully applied to provide information on heat dissipation in these devices. We demonstrate the quantitative measurements of the temperature profiles and high-resolution temperature maps on the front facet of nitride lasers and prove that thermoreflectance spectroscopy can be considered as the accurate and fast nondestructive tool for investigation of thermally induced degradation modes of GaN lasers.

  7. Laser-induced breakdown spectroscopy for real time and online elemental analysis

    CERN Document Server

    Rai, V N; Yueh, Fang-Yu; Singh, J P

    2014-01-01

    Laser-induced breakdown spectroscopy (LIBS) is a laser based diagnostics used to study atomic emission from the expanding plasma plume formed during the laser-matter interaction. It provides valuable information about the composition of the target material. LIBS has proved its potential application in the analysis of impurities, pollutants and toxic elements in various types of matrices of different samples (solid, liquid and gases), even those present under difficult and harsh environmental conditions. This article reviews some recent developments in the field, and its wide application in various fields of research and analysis.

  8. Non-gated laser-induced breakdown spectroscopy in bulk water by position-selective detection

    Energy Technology Data Exchange (ETDEWEB)

    Tian, Ye; Xue, Boyang; Song, Jiaojian; Lu, Yuan; Zheng, Ronger, E-mail: rzheng@ouc.edu.cn [Optics and Optoelectronics Laboratory, Ocean University of China, Qingdao 266100 (China)

    2015-09-14

    Temporal and spatial evolutions of the laser-induced plasma in bulk water are investigated using fast imaging and emission spectroscopic techniques. By tightly focusing a single-pulse nanosecond Nd: YAG laser beam into the bulk water, we generate a strongly expanded plasma with high reproducibility. Such a strong expanding plasma enables us to obtain well-resolved spectral lines by means of position-selective detection; hence, the time-gated detector becomes abdicable. The present results suggest not only a possible non-gated approach for underwater laser-induced breakdown spectroscopy but also give an insight into the plasma generation and expansion in bulk water.

  9. Single-order laser high harmonics in XUV for ultrafast photoelectron spectroscopy of molecular wavepacket dynamics

    Directory of Open Access Journals (Sweden)

    Mizuho Fushitani

    2016-11-01

    Full Text Available We present applications of extreme ultraviolet (XUV single-order laser harmonics to gas-phase ultrafast photoelectron spectroscopy. Ultrashort XUV pulses at 80 nm are obtained as the 5th order harmonics of the fundamental laser at 400 nm by using Xe or Kr as the nonlinear medium and separated from other harmonic orders by using an indium foil. The single-order laser harmonics is applied for real-time probing of vibrational wavepacket dynamics of I2 molecules in the bound and dissociating low-lying electronic states and electronic-vibrational wavepacket dynamics of highly excited Rydberg N2 molecules.

  10. Development of Advanced Seed Laser Modules for Lidar and Spectroscopy Applications

    Science.gov (United States)

    Prasad, Narasimha S.; Rosiewicz, Alex; Coleman, Steven M.

    2013-01-01

    We report on recent progress made in the development of highly compact, single mode, distributed feedback laser (DFB) seed laser modules for lidar and spectroscopy applications from space based platforms. One of the intended application of this technology is in the NASA's Active Sensing of CO2 Emissions over Nights, Days, and Seasons (ASCENDS) mission. The DFB laser modules operating at 1571 nm and 1262 nm have advanced current and temperature drivers built into them. A combination of temperature and current tuning allows coarse and fine adjustment of the diode wavelengths.

  11. Fiber-Based Laser Transmitter for Oxygen A-Band Spectroscopy and Remote Sensing

    Science.gov (United States)

    Stephen, Mark A.; Abshire, James B.

    2010-01-01

    A fiber-based laser transmitter has been designed for active remote-sensing spectroscopy. The transmitter uses a master-oscillator-power-amplifier (MOPA) configuration with a distributed feedback diode-laser master oscillator and an erbium-doped fiber amplifier. The output from the MOPA is frequency-doubled with a periodically poled nonlinear crystal. The utility of this single-frequency, wavelength-tunable, power-scalable laser has been demonstrated in a spectroscopic measurement of the diatomic oxygen A-band.

  12. Laser spectroscopy of rare earth ions in lead borate glasses and transparent glass-ceramics

    Science.gov (United States)

    Pisarski, W. A.; Grobelny, Ł.; Pisarska, J.; Lisiecki, R.; Dominiak-Dzik, G.; Ryba-Romanowski, W.

    2010-03-01

    Rare earth doped lead borate glasses and transparent glass-ceramics have been studied using optical spectroscopy. Based on the absorption, emission and its decay and the Judd-Ofelt calculations, several radiative and laser parameters for Ln 3+ ( Ln = Pr, Nd, Eu, Dy, Er, Tm) were evaluated. The large values of luminescence lifetime, quantum efficiency of excited state and room temperature peak stimulated emission cross-section suggest efficient laser transitions of Ln 3+ ions in lead borate glasses. The obtained results indicate that lead borate glasses and glass-ceramics containing Ln 3+ ions are promising host matrices for solid-state laser applications.

  13. Photoacoustic overtone spectroscopy of liquids with continuous wave laser excitation

    Science.gov (United States)

    Manzares, Carlos; I

    1991-06-01

    To study overtone absorptions in condensed phases, a technique is presented which uses a piezoelectric detector, lock-in amplification and a cw dye laser modulated at frequencies from 10 to 120 kHz with an acousto-optic modulator. Acoustic resonance frequencies calculated for a cylindrical cell are observed experimentally using liquid Si(CH 3) 4 as the sample. The acoustic signal is found to be proportional to the laser power. The fifth overtone of the CH streching mode of Si(CH 3) 4 has been recorded pure and in solutions with CCl 4. With a 1% solution of Si(CH 3) 4 in CCl 4, an absorbance of approximately 1 × 10 -5 cm -1 is detected with a dye laser power of 55 mW.

  14. Laser spectroscopy and photochemistry on metal surfaces, pt.1

    CERN Document Server

    Dai, HL

    1995-01-01

    Using lasers to induce and probe surface processes has the advantages of quantum state specificity, species selectivity, surface sensitivity, fast time-resolution, high frequency resolution, and accessibility to full pressure ranges. These advantages make it highly desirable to use light to induce, control, or monitor surface chemical and physical processes. Recent applications of laser based techniques in studying surface processes have stimulated new developments and enabled the understanding of fundamental problems in energy transfer and reactions. This volume will include discussions on sp

  15. Laser spectroscopy and photochemistry on metal surfaces, pt.2

    CERN Document Server

    Dai, HL

    1995-01-01

    Using lasers to induce and probe surface processes has the advantages of quantum state specificity, species selectivity, surface sensitivity, fast time-resolution, high frequency resolution, and accessibility to full pressure ranges. These advantages make it highly desirable to use light to induce, control, or monitor surface chemical and physical processes. Recent applications of laser based techniques in studying surface processes have stimulated new developments and enabled the understanding of fundamental problems in energy transfer and reactions. This volume will include discussions on sp

  16. Laser synthesis and spectroscopy of acetonitrile/silver nanoparticles

    Science.gov (United States)

    Akin, S. T.; Liu, X.; Duncan, M. A.

    2015-11-01

    Silver nanoparticles with acetonitrile ligands are produced in a laser ablation flow reactor. Excimer laser ablation produces gas phase metal clusters which are thermalized with helium or argon collisions in the flowtube, and reactions with acetonitrile vapor coordinate this ligand to the particle surface. The gaseous mixture is captured in a cryogenic trap; warming produces a solution of excess ligand and coated particles. TEM images reveal particle sizes of 10-30 nm diameter. UV-vis absorption and fluorescence spectra are compared to those of standard silver nanoparticles with surfactant coatings. Deep-UV ligand absorption is strongly enhanced by nanoparticle adsorption.

  17. Advancements in time-resolved x-ray laser induced time-of-flight photoelectron spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, A J; Dunn, J; Widmann, K; Ao, T; Ping, Y; Hunter, J; Ng, A

    2005-07-28

    Time-resolved soft x-ray photoelectron spectroscopy is used to probe the non-steady-state evolution of the valence band electronic structure of laser heated ultra-thin (50 nm) metal foils and bulk semiconductors. Single-shot soft x-ray laser induced time-of-flight photoelectron spectroscopy with picosecond time resolution was used in combination with optical measurements of the disassembly dynamics that have shown the existence of a metastable liquid phase in fs-laser heated metal foils persisting 4-5 ps. This metastable phase is studied using a 527 nm wavelength 400 fs laser pulse containing 0.3-2.5 mJ laser energy focused in a large 500 x 700 {micro}m{sup 2} spot to create heated conditions of 0.2-1.8 x 10{sup 12} W cm{sup -2} intensity. The unique LLNL COMET compact tabletop soft x-ray laser source provided the necessary high photon flux, highly monoenergetic, picosecond pulse duration, and coherence for observing the evolution of changes in the valence band electronic structure of laser heated metals and semiconductors with picosecond time resolution. This work demonstrates the continuing development of a powerful new technique for probing reaction dynamics and changes of local order on surfaces on their fundamental timescales including phenomena such as non-thermal melting, chemical bond formation, intermediate reaction steps, and the existence of transient reaction products.

  18. Determination of Different Metals in Steel Waste Samples Using laser Induced Breakdown Spectroscopy

    Directory of Open Access Journals (Sweden)

    A. H. Bakry

    2007-12-01

    Full Text Available Elemental analysis of waste samples collected from steel products manufacturing plant (SPS located at industrial city of Jeddah, Saudi-Arabia has been carried out using Laser Induced Breakdown Spectroscopy (LIBS. The 1064 nm laser radiations from a Nd:YAG laser at an irradiance of 7.6  1010 W cm –2 were used. Atomic emission spectra of the elements present in the waste samples were recorded in the 200 – 620 nm region. Elements such as Fe, W, Ti, Al, Mg, Ca, S, Mn, and Na were detected in these samples. Quantitative determination of the elemental concentration was obtained for these metals against certified standard samples. Parametric dependences of LIBS signal intensity on incident laser energy and time delay between the laser pulse and data acquisition system were also carried out.

  19. Characterization of femtosecond laser-induced breakdown spectroscopy (fsLIBS) and applications for biological samples.

    Science.gov (United States)

    Gill, Ruby K; Knorr, Florian; Smith, Zachary J; Kahraman, Mehmet; Madsen, Dorte; Larsen, Delmar S; Wachsmann-Hogiu, Sebastian

    2014-01-01

    We characterize the femtosecond laser-induced breakdown spectroscopy (fsLIBS) signal for biological tissues as a function of different excitation parameters with femtosecond laser systems. These parameters include laser energy, depth of focus, and number of pulses per focal volume. We used femtosecond laser pulses of 800 nm and energy between 25 and 123 μJ to generate LIBS signals in biological tissues. As expected, we observed a linear increase in the fsLIBS intensity as a function of the laser energy. In addition, we show that moving the beam out of focus and the presence of overlapping pulses on the same focal area leads to a decrease in fsLIBS intensity due to changes in focal spot size. We also demonstrate that fsLIBS can distinguish between different biological tissue samples.

  20. Broadband spectroscopy with external cavity quantum cascade lasers beyond conventional absorption measurements.

    Science.gov (United States)

    Lambrecht, Armin; Pfeifer, Marcel; Konz, Werner; Herbst, Johannes; Axtmann, Felix

    2014-05-07

    Laser spectroscopy is a powerful tool for analyzing small molecules, i.e. in the gas phase. In the mid-infrared spectral region quantum cascade lasers (QCLs) have been established as the most frequently used laser radiation source. Spectroscopy of larger molecules in the gas phase, of complex mixtures, and analysis in the liquid phase requires a broader tuning range and is thus still the domain of Fourier transform infrared (FTIR) spectroscopy. However, the development of tunable external cavity (EC) QCLs is starting to change this situation. The main advantage of QCLs is their high spectral emission power that is enhanced by a factor of 10(4) compared with thermal light sources. Obviously, transmission measurements with EC-QCLs in strongly absorbing samples are feasible, which can hardly be measured by FTIR due to detector noise limitations. We show that the high power of EC-QCLs facilitates spectroscopy beyond simple absorption measurements. Starting from QCL experiments with liquid samples, we show results of fiber evanescent field analysis (FEFA) to detect pesticides in drinking water. FEFA is a special case of attenuated total reflection spectroscopy. Furthermore, powerful CW EC-QCLs enable fast vibrational circular dichroism (VCD) spectroscopy of chiral molecules in the liquid phase - a technique which is very time consuming with standard FTIR equipment. We present results obtained for the chiral compound 1,1'-bi-2-naphthol (BINOL). Finally, powerful CW EC-QCLs enable the application of laser photothermal emission spectroscopy (LPTES). We demonstrate this for a narrowband and broadband absorber in the gas phase. All three techniques have great potential for MIR process analytical applications.

  1. Monitoring of potential cytotoxic and inhibitory effects of titanium dioxide using on-line and non-invasive cell-based impedance spectroscopy.

    Science.gov (United States)

    Male, Keith B; Hamzeh, Mahsa; Montes, Johnny; Leung, Alfred C W; Luong, John H T

    2013-05-13

    Titanium dioxide (TiO2) nanoparticles (NPs) with different sizes and structures were probed for plausible cytotoxicity using electric cell-substrate impedance sensing (ECIS), a non-invasive and on-line procedure for continuous monitoring of cytotoxicity. For insect cells (Spodoptera frugiperda Sf9), the ECIS50 values, i.e., the concentration required to achieve 50% inhibition of the response, differed depending on the size and shape of the TiO2 nanostructure. The lowest ECIS50 value (158 ppm) was observed for the needle shaped rutile TiO2 (10 nm×40 nm, 15.5 nm nominal particle size), followed by 211 ppm for P-25 (34.1 nm, 80% anatase and 20% rutile), 302 ppm for MTI5 (5.9 nm, 99% anatase) and 417 ppm for Hombitan LW-S bulk TiO2 (169.5 nm, 99% anatase). Exposure of TiO2 NPs to UV light at 254 nm or 365 nm exhibited no significant effect on the ECIS50 value due to the aggregation of TiO2 NPs with diminishing photocatalytic activities. Chinese hamster lung fibroblast V79 cells, exhibited no significant cytotoxicity/inhibition up to 400 ppm with P25, MTI5 and bulk TiO2. However, a noticeable inhibitory effect was observed (ECIS50 value of 251 ppm) with rutile TiO2 as cell spreading on the electrode surface was prevented.

  2. Multicomponent gas analysis using broadband quantum cascade laser spectroscopy

    NARCIS (Netherlands)

    Reyes Reyes, A.; Hou, Z.; Van Mastrigt, E.; Horsten, R.C.; De Jongste, J.C.; Pijnenburg, M.W.; Urbach, H.P.; Bhattacharya, N.

    2014-01-01

    We present a broadband quantum cascade laser-based spectroscopic system covering the region between 850 and 1250 cm−1. Its robust multipass cavity ensures a constant interaction length over the entire spectral region. The device enables the detection and identification of numerous molecules present

  3. Multicomponent gas analysis using broadband quantum cascade laser spectroscopy

    NARCIS (Netherlands)

    Reyes Reyes, A.; Hou, Z.; Van Mastrigt, E.; Horsten, R.C.; De Jongste, J.C.; Pijnenburg, M.W.; Urbach, H.P.; Bhattacharya, N.

    2014-01-01

    We present a broadband quantum cascade laser-based spectroscopic system covering the region between 850 and 1250 cm−1. Its robust multipass cavity ensures a constant interaction length over the entire spectral region. The device enables the detection and identification of numerous molecules present

  4. Cavity ring down spectroscopy with a free-electron laser

    NARCIS (Netherlands)

    Engeln, R.; van den Berg, E.; Meijer, G.; Lin, L.; Knippels, G.M.H.; van der Meer, A. F. G.

    1997-01-01

    A cavity ring down (CRD) absorption experiment is performed with a free-electron laser (FEL) operating in the 10-11 mu m region. A short infrared pulse of approximately 20 ns, sliced from the much longer FEL pulse, is used to measure CRD spectra of ethylene in two different ways. First, ''

  5. NON-INVASIVE SPECTROSCOPIC ON-LINE METHODS TO MONITOR INDUSTRIAL PROCESSES

    DEFF Research Database (Denmark)

    Brooker, M. H.; Berg, Rolf W.

    2003-01-01

    Vibrational spectroscopy can be used to identify and establish concentrations of many common molecules and complex ions over a wide range of concentrations and conditions. Advances in CCD detection devices, notch-filters, lasers, micro- and fiber-optics have made it possible to use infrared and R......, studied with non-invasive Raman spectroscopy), and finally a discussion of some recent advances in experimental methods that make it possible to use Raman and infrared spectroscopy for on line analyses in some industrial applications.......Vibrational spectroscopy can be used to identify and establish concentrations of many common molecules and complex ions over a wide range of concentrations and conditions. Advances in CCD detection devices, notch-filters, lasers, micro- and fiber-optics have made it possible to use infrared...

  6. Study of gas exchange in insects by sensitive laser photoacoustic spectroscopy

    NARCIS (Netherlands)

    Persijn, S.T.; Harren, F.J.M.; Wijkamp, I.; Mitrayana, L.

    2006-01-01

    Although quantifying gas exchange in small insect species is of great biological interest, the progress in this field of research is hampered by the inability of most gas detectors to monitor the low emission rates from these insects. Recently, laser based photoacoustic spectroscopy (LPAS) has emerg

  7. Monitoring Cerebral perfusion using near infrared spectroscopy and laser doppler flowmetry

    NARCIS (Netherlands)

    Klaessens, J.H.G.M.; Kolkman, R.G.M.; Hopman, J.C.W.; Hondebrink, E.; Liem, K.D.; Steenbergen, W.; Mul, de F.F.M.; Thijssen, J.M.

    2003-01-01

    This paper describes the simultaneous use of two, noninvasive, near-infrared techniques near-infrared spectroscopy (NIRS) and a continuous wave NIR laser Doppler flow system (LDF) to measure changes in the blood oxygenation, blood concentration and blood flow velocity in the brain. A piglet was used

  8. Monitoring cerebral perfusion using near-infrared spectroscopy and laser Doppler flowmetry.

    NARCIS (Netherlands)

    Klaessens, J.H.G.M.; Kolkman, R.G.; Hopman, J.C.W.; Hondebrink, E.; Liem, K.D.; Steenbergen, W.; Mul, F.F. de; Thijssen, J.M.

    2003-01-01

    This paper describes the simultaneous use of two, noninvasive, near-infrared techniques near-infrared spectroscopy (NIRS) and a continuous wave NIR laser Doppler flow system (LDF) to measure changes in the blood oxygenation, blood concentration and blood flow velocity in the brain. A piglet was used

  9. Laser-induced breakdown spectroscopy for quantification of heavy metals in soils and sediments

    CSIR Research Space (South Africa)

    Ambushe, AA

    2010-09-01

    Full Text Available Laser-induced breakdown spectroscopy (LIBS) will be used to determine the contents of heavy metals in soils and sediments. LIBS results will be compared with the results obtained by inductively coupled plasma-optical emission spectrometry (ICP...

  10. Study of gas exchange in insects by sensitive laser photoacoustic spectroscopy

    NARCIS (Netherlands)

    Persijn, S.T.; Harren, F.J.M.; Wijkamp, I.; Mitrayana, L.

    2006-01-01

    Although quantifying gas exchange in small insect species is of great biological interest, the progress in this field of research is hampered by the inability of most gas detectors to monitor the low emission rates from these insects. Recently, laser based photoacoustic spectroscopy (LPAS) has

  11. Laser correlation spectroscopy in the diagnosis of tumor diseases of the female reproductive system (preliminary results)

    Science.gov (United States)

    Korneeva, A. A.; Sekerskaya, M. N.; Zhordaniya, K. I.; Sapezhinskiy, V. S.; Golubtsova, N. V.; Barmashov, A. E.; Gonchukov, S. A.; Ivanov, A. V.

    2017-01-01

    The study of blood serum of cancer patients by laser correlation spectroscopy to determine the possibility of differentiation of benign and malignant tumors of the female reproductive system. We analyzed the data and assessed the applicability of the method mentioned above target.

  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. Quantification of metals in preservatively-treated lumber using laser induced breakdown spectroscopy

    Science.gov (United States)

    Brad Gething; John Janowiak; Bob Falk

    2006-01-01

    The laser induced breakdown spectroscopy (LIBS) technique was evaluated for its capability of quantifying CCA in preservative-treated wood. The results of the study reveal that the LIBS technique can be used to predict the amount of preservative based on chromium peak analysis, but further refinement of the process is necessary before the technique is practiced. The...

  14. Use of laser induced breakdown spectroscopy for the analysis of poultry products

    Science.gov (United States)

    Laser Induced Breakdown Spectroscopy is evaluated as a potential method to characterize a wide range of poultry product quality and safety characteristics. In one part of this study, breast meat quality indices, including pH and water holding capacity, were treated as dependent variables for correla...

  15. North American Symposium on Laser Induced Breakdown Spectroscopy (NASLIBS): introduction to feature issue.

    Science.gov (United States)

    Singh, Jagdish P; Almirall, Jose; Sabsabi, Mohamad; Miziolek, Andrzej W

    2012-03-01

    This feature issue highlights the topics of the 2011 North American Symposium on Laser Induced Breakdown Spectroscopy (NASLIBS). These include LIBS application to Security and Forensic, Biomedical and Environmental, Liquid Analysis and Fundamentals of LIBS, Instrumentation/Commercialization, Fusion with LIBS, and New Frontiers. © 2012 Optical Society of America

  16. Online sensor system based on laser-induced breakdown spectroscopy in quality inspection of demolition concrete

    NARCIS (Netherlands)

    Xia, H.; Bakker, M.C.M.

    2012-01-01

    In the C2CA project, an online sensor system is required to measure and control the quality and homogeneity of demolition concrete continuously. Laser-induced breakdown spectroscopy is a candidate to fulfil the objective in several tasks. Investigated is the ability of LIBS as an online

  17. Assaying total carotenoids in flours of corn and sweet potato flours by laser photoacoustic spectroscopy

    NARCIS (Netherlands)

    Luterotti, S.; Bicanic, D.D.; Kijak, K.; Grbesa, D.; Martinez, E.; Spruijt, R.B.

    2011-01-01

    This study describes the application of the laser photoacoustic spectroscopy (PAS) for quantification of total carotenoids (TC) in corn flours and sweetpotato flours. Overall, thirty-three different corn flours and nine sweetpotato flours were investigated. All PAS measurements were performed at roo

  18. Fast single-photon avalanche diode arrays for laser Raman spectroscopy

    NARCIS (Netherlands)

    Blacksberg, J.; Maruyama, Y.; Charbon, E.; Rossman, G.R.

    2011-01-01

    We incorporate newly developed solid-state detector technology into time-resolved laser Raman spectroscopy, demonstrating the ability to distinguish spectra from Raman and fluorescence processes. As a proof of concept, we show fluorescence rejection on highly fluorescent mineral samples willemite an

  19. Calculation and optimization of sample identification by laser induced breakdown spectroscopy via correlation analysis

    NARCIS (Netherlands)

    Lentjes, M.; Dickmann, K.; Meijer, J.

    2007-01-01

    Linear correlation analysis may be used as a technique for the identification of samples with a very similar chemical composition by laser induced breakdown spectroscopy. The spectrum of the “unknown” sample is correlated with a library of reference spectra. The probability of identification by

  20. Fast single-photon avalanche diode arrays for laser Raman spectroscopy

    NARCIS (Netherlands)

    Blacksberg, J.; Maruyama, Y.; Charbon, E.; Rossman, G.R.

    2011-01-01

    We incorporate newly developed solid-state detector technology into time-resolved laser Raman spectroscopy, demonstrating the ability to distinguish spectra from Raman and fluorescence processes. As a proof of concept, we show fluorescence rejection on highly fluorescent mineral samples willemite an

  1. Femtosecond laser induced breakdown spectroscopy of silver within surrogate high temperature gas reactor fuel coated particles

    CSIR Research Space (South Africa)

    Roberts, DE

    2010-11-01

    Full Text Available been studied with femtosecond Laser Induced Breakdown Spectroscopy (femto-LIBS). The SiC layer of the TRISO coated particle is the main barrier to metallic and gaseous fission products of which 110mAg is of particular interest for direct cycle high...

  2. Ultra-short laser pulse ablation using shear-force feedback: Femtosecond laser induced breakdown spectroscopy feasibility study

    Energy Technology Data Exchange (ETDEWEB)

    Samek, Ota [ISAS-Institute for Analytical Sciences, Bunsen-Kirchhoff Str.11, 44139 Dortmund (Germany)]. E-mail: samek@ansci.de; Kurowski, Andre [ISAS-Institute for Analytical Sciences, Bunsen-Kirchhoff Str.11, 44139 Dortmund (Germany); Kittel, Silke [ISAS-Institute for Analytical Sciences, Bunsen-Kirchhoff Str.11, 44139 Dortmund (Germany); Kukhlevsky, Sergei [Institute of Physics, University of Pecs, Ifjusag u. 6, Pecs 7624 (Hungary); Hergenroeder, Roland [ISAS-Institute for Analytical Sciences, Bunsen-Kirchhoff Str.11, 44139 Dortmund (Germany)

    2005-08-31

    This work reports on a feasibility study of proximity ablation using femtosecond pulses. Ultra-short pulses were launched to a bare tapered optical fiber and delivered to the sample. The tip-sample distance was controlled by means of shear-force feedback. Consequently, ablation craters with submicrometer dimensions were obtained. Potential analytical applications for Laser Induced Breakdown Spectroscopy (LIBS) technique, such as e.g. inclusions in steel or bio cells, are suggested.

  3. Laser Infrared Desorption Spectroscopy to Detect Complex Organic Molecules on Icy Planetary Surfaces

    Science.gov (United States)

    Sollit, Luke S.; Beegle, Luther W.

    2008-01-01

    Laser Desorption-Infrared Spectroscopy (LD-IR) uses an IR laser pulse to desorb surface materials while a spectrometer measures the emission spectrum of the desorbed materials (Figure 1). In this example, laser desorption operates by having the incident laser energy absorbed by near surface material (10 microns in depth). This desorption produces a plume that exists in an excited state at elevated temperatures. A natural analog for this phenomenon can be observed when comets approach the sun and become active and individual molecular emission spectra can be observed in the IR [1,2,3,4,5]. When this occurs in comets, the same species that initially emit radiation down to the ground state are free to absorb it, reducing the amount of detectable emission features. The nature of our technique results in absorption not occurring, because the laser pulse could easily be moved away form the initial desorption plume, and still have better spatial resolution then reflectance spectroscopy. In reflectance spectroscopy, trace components have a relatively weak signal when compared to the entire active nature of the surface. With LDIR, the emission spectrum is used to identify and analyze surface materials.

  4. Laser Infrared Desorption Spectroscopy to Detect Complex Organic Molecules on Icy Planetary Surfaces

    Science.gov (United States)

    Sollit, Luke S.; Beegle, Luther W.

    2008-01-01

    Laser Desorption-Infrared Spectroscopy (LD-IR) uses an IR laser pulse to desorb surface materials while a spectrometer measures the emission spectrum of the desorbed materials (Figure 1). In this example, laser desorption operates by having the incident laser energy absorbed by near surface material (10 microns in depth). This desorption produces a plume that exists in an excited state at elevated temperatures. A natural analog for this phenomenon can be observed when comets approach the sun and become active and individual molecular emission spectra can be observed in the IR [1,2,3,4,5]. When this occurs in comets, the same species that initially emit radiation down to the ground state are free to absorb it, reducing the amount of detectable emission features. The nature of our technique results in absorption not occurring, because the laser pulse could easily be moved away form the initial desorption plume, and still have better spatial resolution then reflectance spectroscopy. In reflectance spectroscopy, trace components have a relatively weak signal when compared to the entire active nature of the surface. With LDIR, the emission spectrum is used to identify and analyze surface materials.

  5. Continuous-flow separation and pre-concentration coupled on-line to solid-surface fluorescence spectroscopy for the simultaneous determination of o-phenylphenol and thiabendazole.

    Science.gov (United States)

    García Reyes, J F; Llorent Martínez, E J; Ortega Barrales, P; Molina Díaz, A

    2004-01-01

    A novel and single flow-injection system combined with solid-surface fluorescence detection is proposed in this work for the resolution of a mixture of two widely used pesticides (o-phenylphenol and thiabendazole). The continuous-flow methodology is based on the implementation of on-line pre-concentration and separation of both analytes on the surface of C18 silica gel beads placed just inside the flow cell, implemented with gel-phase fluorimetric multi-wavelength detection (using 305/358 and 250/345 nm as excitation/emission wavelengths for thiabendazole and o-phenylphenol, respectively). The separation of the pesticides was possible owing to the different retention/desorption kinetics of their interactions with the solid support in the zone where the stream impinges on the solid material. No previous separation of the analytes before they reach the flow cell is needed thereby simplifying substantially both the procedure and the manifold. By using a sample volume of 2,600 microL, the system was calibrated in the range 0.5-16 and 5-120 ng mL(-1) with detection limits of 0.09 and 0.60 ng mL(-1) for thiabendazole and o-phenylphenol, respectively. The RSD values (n=10) were about 1% for both analytes. The proposed methodology was applied to environmental water samples and also to various commercial pesticide formulations containing both analytes. Recovery percentages were 97-103% and 98-102% for thiabendazole and o-phenylphenol, respectively.

  6. Heterodyne Phase-Sensitive Dispersion Spectroscopy in the Mid-Infrared with a Quantum Cascade Laser.

    Science.gov (United States)

    Martín-Mateos, Pedro; Hayden, Jakob; Acedo, Pablo; Lendl, Bernhard

    2017-06-06

    Molecular dispersion spectroscopy encompasses a group of spectroscopic techniques for gas analysis that retrieve the characteristics of the sample from the measurement of the profile of its refractive index in the vicinity of molecular resonances. This approach, which is in clear contrast to traditional methods based on the detection of absorption, provides inherent immunity to power fluctuations, calibration-free operation, and an output that is linearly dependent on gas concentration. Heterodyne phase-sensitive dispersion spectroscopy (HPSDS) is a very recently proposed technique for molecular dispersion spectroscopy based on tunable lasers that is characterized by a very simple architecture in which data processing and concentration retrieval are straightforward. Different HPSDS implementations have been experimentally validated in the near-IR. Here, we present the first demonstration of HPSDS in the mid-IR using a directly modulated quantum cascade laser for the measurement of CO. The setup is put under test to characterize its response to changing concentrations, pressures, and levels of optical intensity on the detector, and the limit of detection is estimated. Besides this, an experimental comparison with wavelength modulation spectroscopy with second-harmonic detection (2f-WMS) is performed and discussed in detail in order to offer a clear view of the benefits and drawbacks that HPSDS can provide over what we could consider the reference method for gas analysis based on tunable laser spectroscopy.

  7. Fs–ns double-pulse Laser Induced Breakdown Spectroscopy of copper-based-alloys: Generation and elemental analysis of nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Guarnaccio, A.; Parisi, G.P.; Mollica, D. [CNR-ISM, U.O.S. Tito Scalo, Zona Industriale, 85050 Tito Scalo, PZ (Italy); De Bonis, A. [CNR-ISM, U.O.S. Tito Scalo, Zona Industriale, 85050 Tito Scalo, PZ (Italy); Dipartimento di Scienze, Università degli Studi della Basilicata, Via dell' Ateneo Lucano 10, 85100 Potenza (Italy); Teghil, R. [Dipartimento di Scienze, Università degli Studi della Basilicata, Via dell' Ateneo Lucano 10, 85100 Potenza (Italy); Santagata, A. [CNR-ISM, U.O.S. Tito Scalo, Zona Industriale, 85050 Tito Scalo, PZ (Italy)

    2014-11-01

    laser were representative of the different targets employed. • LIBS can be a powerful tool for on-line monitoring of NP elemental composition.

  8. An effective method for trapping ion beams in superfluid helium for laser spectroscopy experiments

    Directory of Open Access Journals (Sweden)

    Yang X.F

    2014-03-01

    Full Text Available A novel laser spectroscopy technique -“OROCHI” (Optical Radioisotopes Observation in Condensed Helium as Ion-catcher has been proposed. This method aimed to investigate the structure of exotic nuclei systematically by measuring nuclear spins and moments. For in-situ laser spectroscopy of atoms in He II, a method to trap atoms precisely at the observation region of laser is highly needed. In this work, a setup composed of a degrader, two plastic scintillators and a photon detection system is further tested and verified for adjusting and checking the stopping position of 84–87Rb beam. Details of the current setup, experimental results using this method are presented.

  9. Collinear laser spectroscopy of manganese isotopes using optical pumping in ISCOOL

    CERN Multimedia

    Marsh, B A; Neyens, G; Flanagan, K; Rajabali, M M; Reponen, M; Campbell, P; Procter, T J

    Recently, optical pumping of ions has been achieved inside an ion beam cooler-buncher. By illuminating the central axis of the cooler with laser light, subsequent decay populates selected ionic metastable states. This population enhancement is retained as the ion beam is delivered to an experimental station. In the case of collinear laser spectroscopy, transitions can then be excited from a preferred metastable level, rather than the ground-state. This proposal seeks to establish and develop the technique for ISCOOL. As a test of efficiency, this will be applied to the study of $^{55-66}$Mn isotopes using collinear laser spectroscopy-expanding an earlier study where the benefit of the technique was demonstrated. This will provide nuclear spins, magnetic-dipole and electric-quadrupole moments and changes in mean-square charge radii across N = 40 shell closure candidate and into a region where an onset of deformation, and a new "island of inversion" is predicted.

  10. Laser spectroscopy of sub-micrometre- and micrometre-thick caesium-vapour layers

    Energy Technology Data Exchange (ETDEWEB)

    Cartaleva, S; Krasteva, A; Slavov, D; Todorov, P; Vaseva, K [Institute of Electronics, Bulgarian Academy of Sciences, boul. Tzarigradsko shosse 72, 1784 Sofia (Bulgaria); Moi, L [CNISM and Physics Department, University of Siena, via Roma 56, 53100 Siena - Italy (Italy); Sargsyan, A; Sarkisyan, D [Institute for Physical Research, National Academy of Sciences of Armenia, Ashtarak-0203 (Armenia)

    2013-09-30

    We present high resolution laser spectroscopy of Cs vapours confined in a unique optical cell of sub-micrometric and micrometric thickness, where a strong spatial anisotropy is present for the time of interaction between the atoms and laser radiation. Similarly to the spectra of selective specular reflection, the Doppler-free spectra of absorption and fluorescence are observed, not revealing cross-over resonances that will be useful for frequency stabilisation, provided the cell is cheap and compact. A new resonance in the fluorescence of closed transition is studied, demonstrating its high sensitivity to elastic atom – atom and atom – dielectric surface collisions. The theoretical modelling performed is in agreement with the experimental observations. (laser spectroscopy)

  11. Identification of inks and structural characterization of contemporary artistic prints by laser-induced breakdown spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Oujja, M. [Instituto de Quimica Fisica Rocasolano, CSIC, Serrano 119, 28006 Madrid (Spain); Vila, A. [Departament de Pintura, Conservacio-Restauracio, Facultat de Belles Arts, Universitat de Barcelona, Pau Gargallo 4, 08028 Barcelona (Spain); Rebollar, E. [Instituto de Quimica Fisica Rocasolano, CSIC, Serrano 119, 28006 Madrid (Spain); Garcia, J.F. [Departament de Pintura, Conservacio-Restauracio, Facultat de Belles Arts, Universitat de Barcelona, Pau Gargallo 4, 08028 Barcelona (Spain); Castillejo, M. [Instituto de Quimica Fisica Rocasolano, CSIC, Serrano 119, 28006 Madrid (Spain)]. E-mail: marta.castillejo@iqfr.csic.es

    2005-08-31

    Identification of the inks used in artistic prints and the order in which different ink layers have been applied on a paper substrate are important factors to complement the classical stylistic aspects for the authentication of this type of objects. Laser-induced breakdown spectroscopy (LIBS) is investigated to determine the chemical composition and structural distribution of the constituent materials of model prints made by applying one or two layers of several blue and black inks on an Arches paper substrate. By using suitable laser excitation conditions, identification of the inks was possible by virtue of emissions from key elements present in their composition. Analysis of successive spectra on the same spot allowed the identification of the order in which the inks were applied on the paper. The results show the potential of laser-induced breakdown spectroscopy for the chemical and structural characterization of artistic prints.

  12. In situ characterization of few-cycle laser pulses in transient absorption spectroscopy

    CERN Document Server

    Blättermann, Alexander; Kaldun, Andreas; Ding, Thomas; Stooß, Veit; Laux, Martin; Rebholz, Marc; Pfeifer, Thomas

    2016-01-01

    Attosecond transient absorption spectroscopy has thus far been lacking the capability to simultaneously characterize the intense laser pulses at work within a time-resolved quantum-dynamics experiment. However, precise knowledge of these pulses is key to extracting quantitative information in strong-field highly nonlinear light-matter interactions. Here, we introduce and experimentally demonstrate an ultrafast metrology tool based on the time-delay-dependent phase shift imprinted on a strong-field driven resonance. Since we analyze the signature of the laser pulse interacting with the absorbing spectroscopy target, the laser pulse duration and intensity are determined in situ. As we also show, this approach allows for the quantification of time-dependent bound-state dynamics in one and the same experiment. In the future, such experimental data will facilitate more precise tests of strong-field dynamics theories.

  13. In situ characterization of few-cycle laser pulses in transient absorption spectroscopy.

    Science.gov (United States)

    Blättermann, Alexander; Ott, Christian; Kaldun, Andreas; Ding, Thomas; Stooß, Veit; Laux, Martin; Rebholz, Marc; Pfeifer, Thomas

    2015-08-01

    Attosecond transient absorption spectroscopy has thus far been lacking the capability to simultaneously characterize the intense laser pulses at work within a time-resolved quantum-dynamics experiment. However, precise knowledge of these pulses is key to extracting quantitative information in strong-field highly nonlinear light-matter interactions. Here, we introduce and experimentally demonstrate an ultrafast metrology tool based on the time-delay-dependent phase shift imprinted on a strong-field-driven resonance. Since we analyze the signature of the laser pulse interacting with the absorbing spectroscopy target, the laser pulse duration and intensity are determined in situ. As we also show, this approach allows for the quantification of time-dependent bound-state dynamics in one and the same experiment. In the future, such experimental data will facilitate more precise tests of strong-field dynamics theories.

  14. Next generation laser-based standoff spectroscopy techniques for Mars exploration.

    Science.gov (United States)

    Gasda, Patrick J; Acosta-Maeda, Tayro E; Lucey, Paul G; Misra, Anupam K; Sharma, Shiv K; Taylor, G Jeffrey

    2015-01-01

    In the recent Mars 2020 Rover Science Definition Team Report, the National Aeronautics and Space Administration (NASA) has sought the capability to detect and identify elements, minerals, and most importantly, biosignatures, at fine scales for the preparation of a retrievable cache of samples. The current Mars rover, the Mars Science Laboratory Curiosity, has a remote laser-induced breakdown spectroscopy (LIBS) instrument, a type of quantitative elemental analysis, called the Chemistry Camera (ChemCam) that has shown that laser-induced spectroscopy instruments are not only feasible for space exploration, but are reliable and complementary to traditional elemental analysis instruments such as the Alpha Particle X-Ray Spectrometer. The superb track record of ChemCam has paved the way for other laser-induced spectroscopy instruments, such as Raman and fluorescence spectroscopy. We have developed a prototype remote LIBS-Raman-fluorescence instrument, Q-switched laser-induced time-resolved spectroscopy (QuaLITy), which is approximately 70 000 times more efficient at recording signals than a commercially available LIBS instrument. The increase in detection limits and sensitivity is due to our development of a directly coupled system, the use of an intensified charge-coupled device image detector, and a pulsed laser that allows for time-resolved measurements. We compare the LIBS capabilities of our system with an Ocean Optics spectrometer instrument at 7 m and 5 m distance. An increase in signal-to-noise ratio of at least an order of magnitude allows for greater quantitative analysis of the elements in a LIBS spectrum with 200-300 μm spatial resolution at 7 m, a Raman instrument capable of 1 mm spatial resolution at 3 m, and bioorganic fluorescence detection at longer distances. Thus, the new QuaLITy instrument fulfills all of the NASA expectations for proposed instruments.

  15. Iron-Doped Zinc Selenide: Spectroscopy and Laser Development

    Science.gov (United States)

    2014-03-27

    3 PRF pulse repetition frequency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 DPSS diode ...4800 300 2006 Akimov [24] SC ZnSe GS 370 µJ 3950–5050 300 2006 Gallian [25] PC ZnSe GS — 4450 300 2008 Il’ichev [26] PC ZnSe Superluminescence ∼ 1 mJ... diode -pumped solid-state (DPSS) Er:YAG laser modules emitting at 2937 nm with 1.5 W of CW output power are now available [32]. Using beam combination

  16. Applications of ultra-short pulsed laser ablation: thin films deposition and fs/ns dual-pulse laser-induced breakdown spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Teghil, R; De Bonis, A; Galasso, A [Dipartimento di Chimica, Universita della Basilicata, Via N. Sauro 85, 85100 Potenza (Italy); Santagata, A; Albano, G; Villani, P; Spera, D; Parisi, G P [CNR-IMIP, Unita di Potenza, Via S. Loja, 85050 Tito Scalo (Italy)], E-mail: roberto.teghil@unibas.it

    2008-10-15

    In this paper, we report a survey of two of the large number of possible practical applications of the laser ablation performed by an ultra-short pulse laser, namely pulsed laser deposition (PLD) and fs/ns dual-pulse laser-induced breakdown spectroscopy (DP-LIBS). These applications differ from those using just longer pulsed lasers as a consequence of the distinctive characteristics of the plasma produced by ultra-short laser beams. The most important feature of this plasma is the large presence of particles with nanometric size which plays a fundamental role in both applications.

  17. Intracellular protein mass spectroscopy using mid-infrared laser ionization

    Science.gov (United States)

    Awazu, K.; Suzuki, S.

    2007-07-01

    Large-scale analysis of proteins, which can be regarded as functional biomolecule, assumes an important role in the life science. A MALDI using an ultraviolet laser (UV-MALDI) is one of ionization methods without fragmentation and has achieved conformation analysis of proteins. Recently, protein analysis has shifted from conformation analysis to functional and direct one that reserves posttranslational modifications such as the sugar chain addition and phosphorylation. We have proposed a MALDI using a mid-infrared tunable laser (IR-MALDI) as a new ionization method. IR-MALDI is promising because most biomolecules have a specific absorption in mid-infrared range, and IR-MALDI is expected to offer; (1) use of various matrices, (2) use of biomolecules such as water and lipid as the matrix, and (3) super-soft ionization. First, we evaluated the wavelength dependence of ionization of different matrices using a difference frequency generation (DFG) laser, which can tune the wavelength within a range from 5.5 to 10.0 μm. As results, ionization was specifically occurred at 5.8 μm which the C=O vibration stretching bond in matrix material and mass spectrum was observed. Next, protein mass spectrum was observed in the culture cells, MIN6, which secrete insulin, without the conventional cell-preparation processes. We demonstrate that the IR-MALDI has an advantage over the conventional method (UV-MALDI) in direct analysis of intracellular proteins.

  18. Comparing predictive ability of laser-induced breakdown spectroscopy to visible near-infrared spectroscopy for soil property determination

    DEFF Research Database (Denmark)

    Knadel, Maria; Gislum, René; Hermansen, Cecilie

    2017-01-01

    Soil organic carbon (SOC) and particle size fractions have a practical value for agronomy and the environment. Thus, alternative techniques to replace the expensive conventional analyses of soil are needed. Visible near-infrared reflectance spectroscopy (viseNIRS) has already shown potential...... for becoming an alternative method for soil analysis since it is faster and cheaper than conventional methods. Laser-induced breakdown spectroscopy (LIBS) is another cost-effective technique with potential for rapid analysis of elements present in the soil. In this study, the feasibility of using LIBS...... to determine SOC, clay, silt and sand contents of Danish agricultural soils was tested and compared with the viseNIRS method. First, country-scale Partial Least Squares (PLS) regression models on soils collected across Denmark (N ¼ 78) were built and validated using independent field samples (N ¼ 54). Secondly...

  19. NONLINEAR OPTICS: Coherent laser spectroscopy of matter utilizing waveguide structures

    Science.gov (United States)

    Chaus, A. I.; Yashkir, Yu N.

    1990-07-01

    Some features of CARS spectroscopy in waveguide structures are investigated theoretically taking into account stimulated Raman amplification of a weak pump wave in the field of a strong wave and allowing for the phase matching. A four-photon intermode coupling which occurs under amplification conditions results in energy diffusion between different modes. General expressions for the intensities of the pump waves undergoing stimulated amplification and for the anti-Stokes signal are derived and analyzed.

  20. Specific heat flow rate: an on-line monitor and potential control variable of specific metabolic rate in animal cell culture that combines microcalorimetry with dielectric spectroscopy.

    Science.gov (United States)

    Guan, Y; Evans, P M; Kemp, R B

    1998-06-05

    One of the requirements for enhanced productivity by the animal culture systems used in biotechnology is the direct assessment of the metabolic rate by on-line biosensors. Based on the fact that cell growth is associated with an enthalpy change, it is shown that the specific heat flow rate is stoichiometrically related to the net specific rates of substrates, products, and indeed to specific growth rate, and therefore a direct reflection of metabolic rate. Heat flow rate measured by conduction calorimetry has a technical advantage over estimates for many material flows which require assays at a minimum of two discrete times to give the rate. In order to make heat flow rate specific to the amount of the living cellular system, it would be advantageous to divide it by viable biomass. This requirement has been fulfilled by combining a continuous flow microcalorimeter ex situ with a dielectric spectroscope in situ, the latter measuring the viable cell mass volume fraction. The quality of the resulting biosensor for specific heat flow rate was illustrated using batch cultures of Chinese hamster ovary cells (CHO 320) producing recombinant human interferon-gamma (IFN-gamma) during growth in a stirred tank bioreactor under fully aerobic conditions. The measuring scatter of the probe was decreased significantly by applying the moving average technique to the two participant signals. It was demonstrated that the total metabolic rate of the cells, as indicated by the specific heat flow rate sensor, decreased with increasing time in batch culture, coincident with the decline in the two major substrates, glucose and glutamine, and the accumulation of the by-products, ammonia and lactate. Furthermore, the specific heat flow rate was an earlier indicator of substrate depletion than the flow rate alone. The calorimetric-respirometric ratio showed the intensive participation of anaerobic processes during growth and the related IFN-gamma production. Specific heat flow rate was

  1. Emission enhancement using two orthogonal targets in double pulse laser-induced breakdown spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez-Ake, C. [Laboratorio de Fotofisica, Centro de Ciencias Aplicadas y Desarrollo Tecnologico, Universidad Nacional Autonoma de Mexico, Apartado Postal 70-186, Mexico D.F., C.P. 04510 (Mexico)], E-mail: citlali.sanchez@ccadet.unam.mx; Bolanos, Marduk [Laboratorio de Fotofisica, Centro de Ciencias Aplicadas y Desarrollo Tecnologico, Universidad Nacional Autonoma de Mexico, Apartado Postal 70-186, Mexico D.F., C.P. 04510 (Mexico); Ramirez, C.Z. [Colegio de Ciencias y Humanidades Plantel Sur, Universidad Nacional Autonoma de Mexico (Mexico)

    2009-09-15

    The enhancement of emission intensity resulting from the interaction between two laser-induced plasmas on two orthogonal targets was investigated using double pulse laser-induced breakdown spectroscopy (LIBS) at 0.7 Pa, by means of time-resolved spectroscopy and fast photography. The results showed that the interaction between both plasmas improved carbon emission intensity in comparison to a single laser-induced plasma. For all the carbon lines of interest 477.2 nm (CI), 426.7 nm (CII), and 473.4 nm (C{sub 2} Swan band head), the intensity enhancement showed a maximum at a delay between lasers in the range from 2 to 5 {mu}s; moreover it increased with the fluence of the first laser. On the other hand, in the case of C{sub 2} the intensity enhancement reached a maximum at 5 mm from the target; however it decreased with increasing fluence of the second laser. The largest intensity enhancement found was twofold for atomic species and sixfold for molecular species.

  2. A review of the development of portable laser induced breakdown spectroscopy and its applications

    Energy Technology Data Exchange (ETDEWEB)

    Rakovský, J., E-mail: jozef.rakovsky@jh-inst.cas.cz [J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, Dolejškova 3, 18223 Prague 8 (Czech Republic); Čermák, P. [Department of Experimental Physics, Faculty of Mathematics, Physics and Informatics, Comenius University, Mlynská dolina F2, 842 48 Bratislava (Slovakia); Musset, O. [Laboratoire interdisciplinaire Carnot de Bourgogne, UMR CNRS 6303, Université de Bourgogne, BP 47 870, F-21078 Dijon Cedex (France); Veis, P. [Department of Experimental Physics, Faculty of Mathematics, Physics and Informatics, Comenius University, Mlynská dolina F2, 842 48 Bratislava (Slovakia)

    2014-11-01

    In this review, we present person-transportable laser induced breakdown spectroscopy (LIBS) devices that have previously been developed and reported in the literature as well as their applications. They are compared with X-ray fluorescent (XRF) devices, which represent their strongest competition. Although LIBS devices have advantages over XRF devices, such as sensitivity to the light elements, high spatial resolution and the possibility to distinguish between different layers of the sample, there are also disadvantages and both are discussed here. Furthermore, the essential portable LIBS instrumentation (laser, spectrograph and detector) is presented, and published results related to new laser sources (diode-pumped solid-state, microchip and fiber lasers) used in LIBS are overviewed. Compared to conventional compact flashlamp pumped solid-state lasers, the new laser sources provide higher repetition rates, higher efficiency (less power consumption) and higher beam quality, resulting in higher fluences, even for lower energies, and could potentially increase the figure of merit of portable LIBS instruments. Compact spectrometers used in portable LIBS devices and their parts (spectrograph, detector) are also discussed. - Highlights: • Overview of portable LIBS devices transportable by a person • Discussion and new trends about portable LIBS instrumentation: laser, spectrograph and detector • Overview of applications of DPSS, microchip and fiber lasers in LIBS.

  3. 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.

  4. Red emitting monolithic dual wavelength DBR diode lasers for shifted excitation Raman difference spectroscopy

    Science.gov (United States)

    Sumpf, B.; Maiwald, M.; Müller, A.; Bugge, F.; Fricke, J.; Ressel, P.; Pohl, J.; Erbert, G.; Tränkle, G.

    2014-02-01

    Raman lines are often obscured by background light or fluorescence especially when investigating biological samples or samples containing impurities. Shifted excitation Raman difference spectroscopy (SERDS) is a technique to overcome this. By exciting the sample with two slightly shifted wavelengths, it is possible to separate the Raman lines and distortions. In this paper, monolithic dual wavelength DBR diode lasers meeting the demands of Raman spectroscopy and SERDS will be presented. The wavelengths are stabilized and selected by using deeply-etched 10th order surface gratings with different periods manufactured using i-line wafer stepper lithography. Two possible resonator concepts, i.e. a mini-array of two parallel DBR RW-lasers and a Y-branch DBR laser, will be compared. Established excitation wavelengths for Raman spectroscopy at 671 nm and 785 nm are chosen. The total laser length is 3 mm; the ridge width is 2.2 μm for the 785 nm devices and 5 μm for the 671 nm lasers. The length of the DBR gratings is 500 μm. The devices at 671 nm reach output powers up to 100 mW having an emission width smaller than 12 pm (FWHM). The 785 nm lasers show output powers up to 200 mW and a narrow emission below 22 pm. For the dual wavelength lasers the spectral distance between the two excitation lines is about 0.5 nm as targeted. The power consumption at both wavelengths is below 1 W. These data proof that the devices are well suited for their application in portable Raman measurement systems such as handheld devices using SERDS.

  5. Investigation of radial temperature gradients in diode pumped alkali lasers using tunable diode laser absorption spectroscopy

    Science.gov (United States)

    Fox, Charles D.; Perram, Glen P.

    2012-03-01

    Heat loads in Diode Pumped Alkali Lasers (DPAL) have been investigated using a diode laser to probe the radial dependence of the absorbance. A TiS pump laser heats the medium in a T=50-100°C cesium heat pipe with 5 Torr nitrogen used for quenching. A tunable diode laser probes the spectral absorbance of the cesium cell. Local alkali concentration, temperature, and saturation broadening modify Voigt lineshapes in the wing of the hyperfine split lines. The temperature within the pumped volume exceeds the wall temperature by almost 200 C.

  6. SO2 Spectroscopy with A Tunable UV Laser

    Science.gov (United States)

    Morey, W. W.; Penney, C. M.; Lapp, M.

    1973-01-01

    A portion of the fluorescence spectrum of SO2 has been studied using a narrow wavelength doubled dye laser as the exciting source. One purpose of this study is to evaluate the use of SO2 resonance re-emission as a probe of SO2 in the atmosphere. When the SO2 is excited by light at 300.2 nm, for example, a strong reemission peak is observed which is Stokes-shifted from the incident light wavelength by the usual Raman shift (the VI symmetric vibration frequency 1150.5/cm ). The intensity of this peak is sensitive to small changes (.01 nm) in the incident wavelength. Measurements of the N2 quenching and self quenching of this re-emission have been obtained. Preliminary analysis of this data indicates that the quenching is weak but not negligible. The dye laser in our system is pumped by a pulsed N2 laser. Tuning 'and spectral narrowing are accomplished using a telescope-echelle grating combination. In a high power configuration the resulting pulses have a spectral width of about 5 x 10(exp -3) nm and a time duration of about 6 nsec. The echelle grating is rotated by a digital stepping motor, such that each step shifts the wavelength by 6 x 10(exp -4) nm. In addition to the tunable, narrow wavelength uv source and spectral analysis of the consequent re-emission, the system also provides time resolution of the re-emitted light to 6 nsec resolution. This capability is being used to study the lifetime of low pressure S02 fluorescence at different wavelengths and pressures.

  7. Quantification of Lycopene, β-Carotene, and Total Soluble Solids in Intact Red-Flesh Watermelon (Citrullus lanatus) Using On-Line Near-Infrared Spectroscopy.

    Science.gov (United States)

    Tamburini, Elena; Costa, Stefania; Rugiero, Irene; Pedrini, Paola; Marchetti, Maria Gabriella

    2017-04-11

    A great interest has recently been focused on lycopene and β-carotene, because of their antioxidant action in the organism. Red-flesh watermelon is one of the main sources of lycopene as the most abundant carotenoid. The use of near-infrared spectroscopy (NIRS) in post-harvesting has permitted us to rapidly quantify lycopene, β-carotene, and total soluble solids (TSS) on single intact fruits. Watermelons, harvested in 2013-2015, were submitted to near-infrared (NIR) radiation while being transported along a conveyor belt system, stationary and in movement, and at different positions on the belt. Eight hundred spectra from 100 samples were collected as calibration set in the 900-1700 nm interval. Calibration models were performed using partial least squares (PLS) regression on pre-treated spectra (derivatives and SNV) in the ranges 2.65-151.75 mg/kg (lycopene), 0.19-9.39 mg/kg (β-carotene), and 5.3%-13.7% (TSS). External validation was carried out with 35 new samples and on 35 spectra. The PLS models for intact watermelon could predict lycopene with R² = 0.877 and SECV = 15.68 mg/kg, β-carotene with R² = 0.822 and SECV = 0.81 mg/kg, and TSS with R² = 0.836 and SECV = 0.8%. External validation has confirmed predictive ability with R² = 0.805 and RMSEP = 16.19 mg/kg for lycopene, R2 = 0.737 and RMSEP = 0.96 mg/kg for β-carotene, and R² = 0.707 and RMSEP = 1.4% for TSS. The results allow for the market valorization of fruits.

  8. Doppler-free spectroscopy on Cs D$_1$ line with a dual-frequency laser

    CERN Document Server

    Hafiz, Moustafa Abdel; De Clercq, Emeric; Boudot, Rodolphe

    2016-01-01

    We report on Doppler-free laser spectroscopy in a Cs vapor cell using a dual-frequency laser system tuned on the Cs D$_1$ line. Using counter-propagating beams with crossed linear polarizations, an original sign-reversal of the usual saturated absorption dip and large increase in Doppler-free atomic absorption is observed. This phenomenon is explained by coherent population trapping (CPT) effects. The impact of laser intensity and light polarization on absorption profiles is reported in both single-frequency and dual-frequency regimes. In the latter, frequency stabilization of two diode lasers was performed, yielding a beat-note fractional frequency stability at the level of $3 \\times 10^{-12}$ at 1 s averaging time. These performances are about an order of magnitude better than those obtained using a conventional single-frequency saturated absorption scheme.

  9. Quantitative Classification of Quartz by Laser Induced Breakdown Spectroscopy in Conjunction with Discriminant Function Analysis

    Directory of Open Access Journals (Sweden)

    A. Ali

    2016-01-01

    Full Text Available A responsive laser induced breakdown spectroscopic system was developed and improved for utilizing it as a sensor for the classification of quartz samples on the basis of trace elements present in the acquired samples. Laser induced breakdown spectroscopy (LIBS in conjunction with discriminant function analysis (DFA was applied for the classification of five different types of quartz samples. The quartz plasmas were produced at ambient pressure using Nd:YAG laser at fundamental harmonic mode (1064 nm. We optimized the detection system by finding the suitable delay time of the laser excitation. This is the first study, where the developed technique (LIBS+DFA was successfully employed to probe and confirm the elemental composition of quartz samples.

  10. An approach of open-path gas sensor based on tunable diode laser absorption spectroscopy

    Institute of Scientific and Technical Information of China (English)

    Hui Xia; Wenqing Liu; Yujun Zhang; Ruifeng Kan; Min Wang; Ying He; Yiben Cui; Jun Ruan; Hui Geng

    2008-01-01

    Tunable diode laser absorption spectroscopy (TDLAS) is a new method to detect trace-gas qualitatively or quantificationally based on the scan characteristic of the diode laser to obtain the absorption spectroscopy in the characteristic absorption region. A time-sharing scanning open-path TDLAS system using two near infrared distributed feedback (DFB) tunable diode lasers is designed to detect CH4 and H2S in leakage of natural gas. A low-cost Fresnel lens is used in this system as receiving optics which receives the laser beam reflected by a solid corner cube reflector with a distance of up to about 60 m. High sensitivity is achieved by means of wavelength-modulation spectroscopy with second-harmonic detection. The minimum detection limits of 1.1 ppm·m for CH4 and 15 ppm·m for H2S are demonstrated with a total optical path of 120 m. The simulation monitoring experiment of nature gas leakage was carried out with this system. According to the receiving light efficiency of optical system and detectable minimum light intensity of detection, the detectable optical path of the system can achieve 1 - 2 km. The sensor is suitable for natural gas leakage monitoring application.

  11. Fiber-based laser transmitter and laser spectroscopy of the oxygen A-band for remote detection of atmospheric pressure

    Science.gov (United States)

    Stephen, Mark Andrew

    The Author reports on the design and construction of an oxygen spectroscopy laser sounding instrument designed to measure atmospheric pressure. This instrument was conceived and designed with a satellite application in mind so we discuss the requirements this places on the instrument and specifically the laser transmitter. We have developed a novel, pulsed, frequency-doubled, fiber-based laser transmitter for use in the instrument. The instrument concept uses the collision broadening of spectroscopic lines of the diatomic oxygen A-band to deduce atmospheric pressure. We report on the spectroscopic and instrument theory. We discuss the development of a high-power, narrow-frequency, tunable, single spatial mode pulsed laser transmitter. The transmitter is a master oscillator power amplifier (MOPA) design. The master oscillator is a fiber coupled DFB laser with external acousto-optic modulation. The amplifier is a diode pumped, erbium-doped fiber. We discuss the non-linear optical effect of stimulated Brillouin scattering (SBS) and how it limits the transmitter performance. We review various methods for overcoming SBS in erbium fiber amplifiers and then demonstrate the performance of a high SBS threshold fiber amplifier. We demonstrate the efficacy of this transmitter by integrating it into a spectroscopic instrument and make atmospheric measurements at a test site at Goddard. We also discuss future improvements.

  12. Study of thymidylate synthetase-function by laser Raman spectroscopy.

    Science.gov (United States)

    Sharma, R K; Kisliuk, R L; Verma, S P; Wallach, D F

    1975-05-23

    The Laser-Raman spectra of thymidylate synthetase have been obtained with 488 nm excitation from an argon ion laser. Raman bands observed in the range 600-800 cm-minus-1 have been assigned to functional groups of constituent amino acids. The band positions and intensities in the Amide I (1600-1700 cm-minus-1) and Amide III (1200-1300 cm-minus-1) regions, suggest that the enzyme is a mixture of alpha-helical and unordered conformations. Low levels of beta-structure cannot be excluded. The spectra of the ternary complex formed by reacting thymidylate synthetase with (+)-L-methylenetetrahydrofolate and fluorodeoxyuridylate reveals a new band at 1618 cm-minus-1 assigned to the C=N stretching vibration. This band may be due to formation of dihydrofolate or an iminium ion. The overall secondary structure of thymidylate synthetase does not change on formation of the ternary complex. However, the spectrum of the complex indicates local changes in groups such as ionized carboxyl (1400 cm-minus-1), tryptophan (1003 cm-minus-1) and CH-3, CH-2 deformation modes (1440-1470 cm-minus-1).

  13. Laser resonance ionization spectroscopy on lutetium for the MEDICIS project

    Energy Technology Data Exchange (ETDEWEB)

    Gadelshin, V., E-mail: gadelshin@uni-mainz.de [University of Mainz, Institute of Physics (Germany); Cocolios, T. [KU Leuven, Institute for Nuclear and Radiation Physics (Belgium); Fedoseev, V. [CERN, EN Department (Switzerland); Heinke, R.; Kieck, T. [University of Mainz, Institute of Physics (Germany); Marsh, B. [CERN, EN Department (Switzerland); Naubereit, P. [University of Mainz, Institute of Physics (Germany); Rothe, S.; Stora, T. [CERN, EN Department (Switzerland); Studer, D. [University of Mainz, Institute of Physics (Germany); Duppen, P. Van [KU Leuven, Institute for Nuclear and Radiation Physics (Belgium); Wendt, K. [University of Mainz, Institute of Physics (Germany)

    2017-11-15

    The MEDICIS-PROMED Innovative Training Network under the Horizon 2020 EU program aims to establish a network of early stage researchers, involving scientific exchange and active cooperation between leading European research institutions, universities, hospitals, and industry. Primary scientific goal is the purpose of providing and testing novel radioisotopes for nuclear medical imaging and radionuclide therapy. Within a closely linked project at CERN, a dedicated electromagnetic mass separator system is presently under installation for production of innovative radiopharmaceutical isotopes at the new CERN-MEDICIS laboratory, directly adjacent to the existing CERN-ISOLDE radioactive ion beam facility. It is planned to implement a resonance ionization laser ion source (RILIS) to ensure high efficiency and unrivaled purity in the production of radioactive ions. To provide a highly efficient ionization process, identification and characterization of a specific multi-step laser ionization scheme for each individual element with isotopes of interest is required. The element lutetium is of primary relevance, and therefore was considered as first candidate. Three two-step excitation schemes for lutetium atoms are presented in this work, and spectroscopic results are compared with data of other authors.

  14. Spectroscopy and Laser-SNMS on stable and radioactive strontium

    Energy Technology Data Exchange (ETDEWEB)

    Bosco, Hauke; Walther, Clemens [Institut fuer Radiooekologie und Strahlenschutz, Leibniz Universitaet Hannover (Germany); Franzmann, Michael [Institut fuer Radiooekologie und Strahlenschutz, Leibniz Universitaet Hannover (Germany); Institut fuer Physik, Johannes Gutenberg Universitaet Mainz (Germany); Kron, Tobias; Wendt, Klaus [Institut fuer Physik, Johannes Gutenberg Universitaet Mainz (Germany)

    2016-07-01

    Nuclear accidents as experienced e.g. in Chernobyl or Fukushima and nuclear weapon tests released considerable activity levels and a variety of medium to long-lived radionuclides into the environment. Strontium-90 appears as a significant share of the fission products in spent nuclear fuel and correspondingly in any possible release. Due to its chemical properties it is subject to long range transport through the environment and can cause considerable dose to man when entering the food chain. Correspondingly, the investigation of speciation and migration channels is of major relevance. A radioanalytical approach is severely hampered by the low beta energy of the strontium-90 decay and the need to separate strontium-90 from the secular equilibrated daughter yttrium-90. Hence, application of a mass spectrometric method without chemical separation of the elements is a promising alternative for low-level investigation of strontium-90. Application of the new Laser-SNMS system at IRS Hannover could well suit those needs. It applies three Ti:Sa lasers for resonant ionization of neutral atoms produced by primary ion sputtering in a SIMS together with a time-of-flight mass analysis which provides high spatial resolution. The analytical measurements are preceded by spectroscopic studies on the level structure of strontium to develop a most efficient ionization scheme.

  15. Laser-induced breakdown spectroscopy analysis of human deciduous teeth samples.

    Science.gov (United States)

    Khalid, Arooj; Bashir, Shazia; Akram, Mahreen; Hayat, Asma

    2015-12-01

    Laser-induced breakdown spectroscopy (LIBS) analysis of human deciduous teeth has been performed by employing Nd:YAG laser (1064 nm, 10 ns) for the evaluation of plasma parameters as well as elemental analysis. The plasma parameters, i.e., electron temperature and electron number density of laser-induced teeth plasma at various fluencies, have been evaluated. Both parameters show an increasing trend up to a certain value of laser fluence, i.e., 2.6 J/cm(2). With further increase in laser fluence up to a value of 3.9 J/cm(2), a decreasing trend is observed which is due to shielding effect. With further increase in laser fluence up to a maximum value of 10.5 J/cm(2), the insignificant changes in plasma parameters are observed which are attributed to saturation phenomenon governed by self-regulating regime. Emission spectroscopy results exhibit that laser fluence is the controlling factor for both plasma parameters. The elemental analysis was also performed at constant laser fluence of 2.6 J/cm(2) by evaluating the variation in detected elemental concentration of Ca, Fe, Sr, Zn, and Pb in three different parts of human teeth, i.e., enamel, dentine, and cementum. The lower concentration of Ca as compared to the standard values of CaCO3 (self-fabricated pellet) reveals that enamel is the most deciduous part of the human teeth. However, at the same time, it is also observed that the highest concentration of micro minerals is also found in enamel, then in dentine, and lowest in cementum. Carious or unhealthy tooth is identified by enhanced concentration of micro minerals (Pb, Sr, Zn, and Fe). The highest concentration of micro minerals as compared to other parts of teeth (dentine and root cementum) and lower concentration of Ca as compared to standard CaCO3 pellet in enamel confirm that enamel is the most deciduous part of the teeth.

  16. Collinear resonant ionization laser spectroscopy of rare francium isotopes

    CERN Multimedia

    Neyens, G; Flanagan, K; Rajabali, M M; Le blanc, F M; Ware, T; Procter, T J

    2008-01-01

    We propose a programme of collinear resonant ionization spectroscopy (CRIS) of the francium isotopes up to and including $^{201}$Fr and $^{218,219}$Fr. This work aims at answering questions on the ordering of quantum states, and effect of the ($\\pi s_{1/2}^{-1}$)1/2$^{+}$ intruder state, which is currently believed to be the ground state of $^{199}$Fr. This work will also study the edge of the region of reflection asymmetry through measurement of the moments and radii of $^{218,219}$Fr. This proposal forms the first part of a series of experiments that will study nuclei in this region of the nuclear chart. Based on the success of this initial proposal it is the intention of the collaboration to perform high resolution measurements on the isotopes of radium and radon that surround $^{201}$Fr and $^{218}$Fr and thus providing a comprehensive description of the ground state properties of this region of the nuclear chart. Recent in-source spectroscopy measurements of lead, bismuth and polonium have demonstrated a...

  17. On-line chemical composition analyzer development

    Energy Technology Data Exchange (ETDEWEB)

    Roberts, M.J.; Garrison, A.A.; Muly, E.C.; Moore, C.F.

    1992-02-01

    The energy consumed in distillation processes in the United States represents nearly three percent of the total national energy consumption. If effective control of distillation columns can be accomplished, it has been estimated that it would result in a reduction in the national energy consumption of 0.3%. Real-time control based on mixture composition could achieve these savings. However, the major distillation processes represent diverse applications and at present there does not exist a proven on-line chemical composition sensor technology which can be used to control these diverse processes in real-time. This report presents a summary of the findings of the second phase of a three phase effort undertaken to develop an on-line real-time measurement and control system utilizing Raman spectroscopy. A prototype instrument system has been constructed utilizing a Perkin Elmer 1700 Spectrometer, a diode pumped YAG laser, two three axis positioning systems, a process sample cell land a personal computer. This system has been successfully tested using industrially supplied process samples to establish its performance. Also, continued application development was undertaken during this Phase of the program using both the spontaneous Raman and Surface-enhanced Raman modes of operation. The study was performed for the US Department of Energy, Office of Industrial Technologies, whose mission is to conduct cost-shared R D for new high-risk, high-payoff industrial energy conservation technologies. Although this document contains references to individual manufacturers and their products, the opinions expressed on the products reported do not necessarily reflect the position of the Department of Energy.

  18. Study on the influence of laser pulse duration in the long nanosecond regime on the laser induced plasma spectroscopy

    Science.gov (United States)

    Elnasharty, I. Y.

    2016-10-01

    By using a high power pulsed fiber laser, this study reports the experimental investigation of the laser-induced plasma characteristics for the laser pulse duration range extended from 40 ns to 200 ns. The experiments were performed with keeping the laser fluence constant at 64 J/cm2. The measurements show that, for the early phase of plasma formation, the spectral line intensities and the continuum emissions as well as the plasma characteristics decay to a certain extent with the increase of the pulse duration. On the other hand, as the plasma evolves in post laser pulse regime, the electron density and the degree of ionization increase slightly for the longer pulses, while the plume temperature is more or less independent from the pulse duration. Furthermore, the ablation characteristics, such as the ablation rate, coincide with the results of plasma characteristics for the different pulse durations. Eventually, with keeping the laser fluence constant at 64 J/cm2, the analytical performance of Laser-Induced Plasma Spectroscopy (LIPS) for the corresponding pulse duration range is examined by using a temporal gating and non-gating analyses. The measurements show that, in the case of gating analysis, all pulse durations yield almost the same range of limits of detections LODs. On the other hand, for non-gating analysis, the longer pulse durations provide lower LODs (better) than the shorter ones by orders of magnitude. Moreover, the calculated absolute limit of detection (LODAbs) for the longest pulse duration (i.e. 200 ns) is lower by approximately factor 2 than that of the shortest one (i.e. 40 ns).

  19. High-speed high-sensitivity infrared spectroscopy using mid-infrared swept lasers (Conference Presentation)

    Science.gov (United States)

    Childs, David T. D.; Groom, Kristian M.; Hogg, Richard A.; Revin, Dmitry G.; Cockburn, John W.; Rehman, Ihtesham U.; Matcher, Stephen J.

    2016-03-01

    Infrared spectroscopy is a highly attractive read-out technology for compositional analysis of biomedical specimens because of its unique combination of high molecular sensitivity without the need for exogenous labels. Traditional techniques such as FTIR and Raman have suffered from comparatively low speed and sensitivity however recent innovations are challenging this situation. Direct mid-IR spectroscopy is being speeded up by innovations such as MEMS-based FTIR instruments with very high mirror speeds and supercontinuum sources producing very high sample irradiation levels. Here we explore another possible method - external cavity quantum cascade lasers (EC-QCL's) with high cavity tuning speeds (mid-IR swept lasers). Swept lasers have been heavily developed in the near-infrared where they are used for non-destructive low-coherence imaging (OCT). We adapt these concepts in two ways. Firstly by combining mid-IR quantum cascade gain chips with external cavity designs adapted from OCT we achieve spectral acquisition rates approaching 1 kHz and demonstrate potential to reach 100 kHz. Secondly we show that mid-IR swept lasers share a fundamental sensitivity advantage with near-IR OCT swept lasers. This makes them potentially able to achieve the same spectral SNR as an FTIR instrument in a time x N shorter (N being the number of spectral points) under otherwise matched conditions. This effect is demonstrated using measurements of a PDMS sample. The combination of potentially very high spectral acquisition rates, fundamental SNR advantage and the use of low-cost detector systems could make mid-IR swept lasers a powerful technology for high-throughput biomedical spectroscopy.

  20. Field detection of CO and CH4 by NIR 2f modulation laser spectroscopy

    Directory of Open Access Journals (Sweden)

    A Khorsandi

    2011-12-01

    Full Text Available   A novel compact fiber-coupled NIR system based on a DFB diode laser source is employed as a portable and sensitive gas sensor for trace detection of combustion pollutant molecules. We demonstrate the performance of such an NIR gas sensor by tracing the absorption lines of CO and CH4 using 2f-WMS technique at moderate temperature of T ~ 600°C in the recuperator channel of an industrial furnace provided by Mobarakeh steel company. This measurement shows the excellent sensitivity of the applied NIR gas sensor to the on-line and in-situ monitoring of such molecular species.

  1. Signal enhancement in laser-induced breakdown spectroscopy using fast square-pulse discharges

    Science.gov (United States)

    Sobral, H.; Robledo-Martinez, A.

    2016-10-01

    A fast, high voltage square-shaped electrical pulse initiated by laser ablation was investigated as a means to enhance the analytical capabilities of laser Induced breakdown spectroscopy (LIBS). The electrical pulse is generated by the discharge of a charged coaxial cable into a matching impedance. The pulse duration and the stored charge are determined by the length of the cable. The ablation plasma was produced by hitting an aluminum target with a nanosecond 532-nm Nd:YAG laser beam under variable fluence 1.8-900 J cm- 2. An enhancement of up to one order of magnitude on the emission signal-to-noise ratio can be achieved with the spark discharge assisted laser ablation. Besides, this increment is larger for ionized species than for neutrals. LIBS signal is also increased with the discharge voltage with a tendency to saturate for high laser fluences. Electron density and temperature evolutions were determined from time delays of 100 ns after laser ablation plasma onset. Results suggest that the spark discharge mainly re-excites the laser produced plume.

  2. Structural changes in nanostructured catalytic oxides monitored by Raman spectroscopy: Effect of the laser heating

    Science.gov (United States)

    Oliveira, Alcemira C.; da Silva, Antonio N.; Junior, Jose Alves L.; Freire, Paulo T. C.; Oliveira, Alcineia C.; Filho, Josué M.

    2017-03-01

    The laser power effects on the structural properties of nanostructured oxides were studied by Raman spectroscopy. The nanostructured CeO2, ZrO2, SnO2, TiO2 and MnOx oxides were prepared by a nanocasting route and characterized through various physicochemical techniques. The structural features of the solids were accompanied by varying the incident laser power from 2.0 to 9.1 mW. The laser caused local heating on the surface of the nanostructured solids and influenced on their particle sizes. The CeO2, TiO2 and MnOx spectra exhibited particle size changes due to thermal effects. Elevated laser power up to 9.1 mW accelerated the sintering of CeO2, TiO2 and MnOx particles in contrast to SnO2 counterparts. Simultaneously, the creation of defects in the aforesaid oxide structures was suggested upon increasing the laser power from 2.0 to 9.1 mW. The phase transformation from MnOx-related phases to α-Mn2O3 and the oxidation of these phases were observed. Tetragonal ZrO2 showed a very stable structure under laser heating, envisaging further catalytic applications upon using mild laser power.

  3. Pilot study of laser induced breakdown spectroscopy for tissue differentiation by monitoring the plume created during laser surgery — An approach on a feedback Laser control mechanism

    Science.gov (United States)

    Kanawade, Rajesh; Mehari, Fanuel; Knipfer, Christian; Rohde, Maximilian; Tangermann-Gerk, Katja; Schmidt, Michael; Stelzle, Florian

    2013-09-01

    This study focuses on tissue differentiation using 'Laser Induced Breakdown Spectroscopy' (LIBS) by monitoring the plasma plume created during laser surgery processes. This technique is aimed at controlling a laser surgery feedback system in real time. An Excimer laser (Ar-F 193 nm) was used for the ablation of tissue samples. Fat, muscle, nerve and skin tissue samples of bisected ex-vivo pig heads were prepared as test objects for the ablation procedure. A single fiber was used to collect emissions and deliver them to a spectrometer. The obtained LIBS spectra in the measured emissions were analyzed to determine each tissue type according to their chemical composition. The elements found in the samples and their emission spectra were in agreement with those described in literature. The collected LIBS spectra were analyzed to differentiate the tissues using statistical data analysis: Principal Component Analysis (PCA), Linear Discriminant Analysis (LDA) and Receiver Operating Characteristics (ROC). The obtained preliminary results suggest a successful differentiation of the target tissues with high sensitivity and specificity. The main goal of this study was to qualitatively identify tissue types during laser ablation, which will provide a real time feedback mechanism for clinical Laser surgery applications to significantly improve the accuracy and safety of laser surgery procedures.

  4. Determination of the Zinc Concentration in Human Fingernails Using Laser-Induced Breakdown Spectroscopy.

    Science.gov (United States)

    Riberdy, Vlora A; Frederickson, Christopher J; Rehse, Steven J

    2017-04-01

    The absolute concentration of Zn in human fingernail clippings was determined ex vivo using 1064 nm laser-induced breakdown spectroscopy and confirmed by speciated isotope dilution mass spectrometry. A nail testing protocol that sampled across the nail (perpendicular to the direction of growth) was developed and validated by scanning electron microscopy energy-dispersive X-ray spectrometry. Using this protocol, a partial least squares (PLS) regression model predicted the Zn concentration in the fingernails of five people to within an average of 7 ppm. The variation in the Zn concentration with depth into the nail determined by laser-induced breakdown spectroscopy was studied and showed no systematic variation for up to 15 subsequent laser pulses in one location. The effects of nail hydration (dehydrated and over-hydrated) and nail surface roughness were investigated to explain an anomalously large scatter observed in the measurements. This scatter was attributed to the layered nature and fibrous structure of the fingernails, which resulted in non-uniform ablation as determined by scanning electron microscopy. This work demonstrates that a protocol consisting of low pulse energy (laser pulses incident on human fingernail clippings in an Ar environment can produce quantifiable Zn emission in the laser-induced plasma and that the measured Zn intensity can be used to accurately predict the Zn concentration in human fingernails.

  5. [Signal analysis and spectrum distortion correction for tunable diode laser absorption spectroscopy system].

    Science.gov (United States)

    Bao, Wei-Yi; Zhu, Yong; Chen, Jun; Chen, Jun-Qing; Liang, Bo

    2011-04-01

    In the present paper, the signal of a tunable diode laser absorption spectroscopy (TDLAS) trace gas sensing system, which has a wavelength modulation with a wide range of modulation amplitudes, is studied based on Fourier analysis method. Theory explanation of spectrum distortion induced by laser intensity amplitude modulation is given. In order to rectify the spectrum distortion, a method of synchronous amplitude modulation suppression by a variable optical attenuator is proposed. To validate the method, an experimental setup is designed. Absorption spectrum measurement experiments on CO2 gas were carried out. The results show that the residual laser intensity modulation amplitude of the experimental system is reduced to -0.1% of its original value and the spectrum distortion improvement is 92% with the synchronous amplitude modulation suppression. The modulation amplitude of laser intensity can be effectively reduced and the spectrum distortion can be well corrected by using the given correction method and system. By using a variable optical attenuator in the TDLAS (tunable diode laser absorption spectroscopy) system, the dynamic range requirements of photoelectric detector, digital to analog converter, filters and other aspects of the TDLAS system are reduced. This spectrum distortion correction method can be used for online trace gas analyzing in process industry.

  6. Ultrasensitive photoacoustic sensor based on quantum cascade laser spectroscopy

    Science.gov (United States)

    Kumar, Deepak; Gautam, Surya; Kumar, Subodh; Gupta, Saurabh; Srivastava, Hari B.; Thakur, Surya N.; Sharma, Ramesh C.

    2017-04-01

    The paper focuses on development of ultra-sonic detection system based on laser photoacoustic spectroscopic technique and processing of signal for detection of very low quantity chemicals, explosive materials, and mixtures of these hazardous molecules. The detection system has been developed for the first time with specially designed one side open photo-acoustic cell having high quality factor. Explosive and Hazardous materials like RDX, DNT, PETN, Gun Powder, TATP (Tri acetone tri-peroxide) and their simulants like Acetone were detected in 7 to 9 μm wavelength band. Lock in amplifier electronic instrument was used for the detection of hazardous chemicals and mixture of explosives in very low quantity. Detection limit of the photoacoustic ultrasonic sensor was also carried out of powder, liquid and adsorbed on surfaces.

  7. Laser spectroscopy with an electrostatic ConeTrap

    Energy Technology Data Exchange (ETDEWEB)

    Kelly, S., E-mail: sam.kelly@postgrad.manchester.ac.uk; Campbell, P. [University of Manchester, Nuclear Physics Group, Schuster Laboratory, Brunswick Street (United Kingdom); Cheal, B., E-mail: Bradley.Cheal@Liverpool.ac.uk [University of Liverpool, Oliver Lodge Laboratory (United Kingdom); Eronen, T.; Geldhof, S.; Jokinen, A.; Moore, I. D.; Penttilä, H.; Pohjalainen, I.; Rinta-Antila, S.; Sonnenschein, V.; Voss, A. [JYFL, University of Jyväskylä (Finland)

    2017-11-15

    A compact electrostatic trap has been designed and installed as part of the recent upgrades to the IGISOL IV facility. The ConeTrap provides an in vacuo optical pumping site for low energy (800 eV) ionic ensembles available for interaction periods of 10-100 ms. At present, 6.7(3) % of injected mass A=98 ions can be trapped, stored for 5 ms, extracted and transported to a laser-ion interaction region. This fraction represents those ions for which no perturbation to total energy or energy spread is observed. Proposed enhancements to the trap are designed to improve the trapping efficiency by up to a factor of 5. Differential pumping and reduction in background pressure below the present 10{sup −6} mbar will extend storage times beyond 100 ms.

  8. Laser tweezers: spectroscopy of optically trapped micron-sized particles

    Energy Technology Data Exchange (ETDEWEB)

    Kerr, K.M.; Livett, M.K.; Nugent, K.W. [Melbourne Univ., Parkville, VIC (Australia). School of Physics

    1996-12-31

    Information is often obtained about biological systems by analysis of single cells in the system. The optimum conditions for this analysis are when the cells are living and in their natural surroundings as they will be performing their normal functions and interactions. Analysis of cells can be difficult due to their mobility. Laser tweezing is a non contact method that can be employed to overcome this problem and provides a powerful tool in the analysis of functions and interactions at single cell level. In this investigation Raman spectra of a molecule of {beta} - carotene, dissolved in microdroplets of oil was obtained. The droplets were trapped using Nd-YAG beam and a low intensity Ar{sup +} beam was used to analyse the trapped particles. 2 refs., 5 figs.

  9. Changes in mean-squared charge radii and magnetic moments of Tl-184179 measured by in-source laser spectroscopy

    Science.gov (United States)

    Barzakh, A. E.; Andreyev, A. N.; Cocolios, T. E.; de Groote, R. P.; Fedorov, D. V.; Fedosseev, V. N.; Ferrer, R.; Fink, D. A.; Ghys, L.; Huyse, M.; Köster, U.; Lane, J.; Liberati, V.; Lynch, K. M.; Marsh, B. A.; Molkanov, P. L.; Procter, T. J.; Rapisarda, E.; Rothe, S.; Sandhu, K.; Seliverstov, M. D.; Sjödin, A. M.; Van Beveren, C.; Van Duppen, P.; Venhart, M.; Veselský, M.

    2017-01-01

    Hyperfine structure and isotope shifts have been measured for the ground and isomeric states in the neutron-deficient isotopes Tl-184179 using the 276.9-nm transition. The experiment has been performed at the CERN-Isotope Separator On-Line facility using the in-source resonance-ionization laser spectroscopy technique. Spins for the ground states in 179,181,183Tl have been determined as I =1 /2 . Magnetic moments and changes in the nuclear mean-square charge radii have been deduced. By applying the additivity relation for magnetic moments of the odd-odd Tl nuclei the leading configuration assignments were confirmed. A deviation of magnetic moments for isomeric states in Tl,184182 from the trend of the heavier Tl nuclei is observed. The charge radii of the ground states of the isotopes Tl-184179 follow the trend for isotonic (spherical) lead nuclei. The noticeable difference in charge radii for ground and isomeric states of Tl,184183 has been observed, suggesting a larger deformation for the intruder-based 9 /2- and 10- states compared to the ground states. An unexpected growth of the isomer shift for 183Tl has been found.

  10. Laser-induced breakdown spectroscopy-based investigation and classification of pharmaceutical tablets using multivariate chemometric analysis.

    Science.gov (United States)

    Myakalwar, Ashwin Kumar; Sreedhar, S; Barman, Ishan; Dingari, Narahara Chari; Venugopal Rao, S; Prem Kiran, P; Tewari, Surya P; Manoj Kumar, G

    2011-12-15

    We report the effectiveness of laser-induced breakdown spectroscopy (LIBS) in probing the content of pharmaceutical tablets and also investigate its feasibility for routine classification. This method is particularly beneficial in applications where its exquisite chemical specificity and suitability for remote and on site characterization significantly improves the speed and accuracy of quality control and assurance process. Our experiments reveal that in addition to the presence of carbon, hydrogen, nitrogen and oxygen, which can be primarily attributed to the active pharmaceutical ingredients, specific inorganic atoms were also present in all the tablets. Initial attempts at classification by a ratiometric approach using oxygen (∼777 nm) to nitrogen (742.36 nm, 744.23 nm and 746.83 nm) compositional values yielded an optimal value at 746.83 nm with the least relative standard deviation but nevertheless failed to provide an acceptable classification. To overcome this bottleneck in the detection process, two chemometric algorithms, i.e. principal component analysis (PCA) and soft independent modeling of class analogy (SIMCA), were implemented to exploit the multivariate nature of the LIBS data demonstrating that LIBS has the potential to differentiate and discriminate among pharmaceutical tablets. We report excellent prospective classification accuracy using supervised classification via the SIMCA algorithm, demonstrating its potential for future applications in process analytical technology, especially for fast on-line process control monitoring applications in the pharmaceutical industry. Copyright © 2011 Elsevier B.V. All rights reserved.

  11. Dual-wavelength Raman spectroscopy approach for studying fluid-phase equilibria using a single laser.

    Science.gov (United States)

    Kiefer, Johannes

    2010-06-01

    A novel Raman spectroscopy setup for the investigation of multiphase fluid mixtures is proposed. The total output of a frequency-doubled Nd:YAG laser is separated into a strong 532 nm beam for generating Raman signals in the vapor phase and the weak residual of the fundamental 1064 nm radiation to be utilized as laser source for Raman scattering in the liquid phase. This approach will provide sufficient signal intensity from the gas (despite low density) for determination of mixture composition and at the same time it facilitates recording high-resolution spectra from the liquid in order to allow studying molecular physics phenomena together with concentration measurements.

  12. First measurement of radioisotopes by collinear laser spectroscopy at an ion-guide separator

    Energy Technology Data Exchange (ETDEWEB)

    Cooke, J.L.; Cochrane, E.C.A.; Evans, D.E.; Griffith, J.A.R.; Persson, J.R.; Richardson, D.S.; Tungate, G.; Zybert, L. [School of Physics and Space Research, University of Birmingham, Edgbaston, Birmingham B15 2TT (United Kingdom); Billowes, J.; Campbell, P.; Cooper, T.G.; Grant, I.S.; Levins, J.M.G.; Pearson, M.R.; Wheeler, P.D. [Schuster Laboratory, University of Manchester, Manchester M13 9PL (United Kingdom); Dendooven, P.; Honkanen, A.; Huhta, M.; Oinonen, M.; Penttilae, H.; Aeystoe, J. [Accelerator Laboratory, University of Jyvaeskylae, PL 35, Jyvaeskylae SF - 403 51 (Finland)

    1997-11-01

    The first successful application of an ion-guide separator (IGISOL) for collinear laser spectroscopy of radioisotopes has achieved an efficiency comparable with the best obtained with catcher-ionizer facilities. The ion beam energy spread was determined to be less than 6 eV, allowing laser fluorescence resonance signals for the {sup 140,142,144}Ba radioisotopes to be detected with high resolution and sensitivity. Applications of this technique to measuring nuclear properties of refractory elements and short lived isomers promises to be particularly advantageous. (author). Letter-to-the-editor.

  13. Optical Autler-Townes spectroscopy in a heteronuclear mixture of laser-cooled atoms

    Science.gov (United States)

    Bruni, C.; Münchow, F.; Görlitz, A.

    2017-01-01

    We report on optical Autler-Townes spectroscopy in a heteronuclear mixture of {}^{87}Rb and {}^{176}Yb in a continuously loaded double-species magneto-optical trap. An excited vibrational level of Rb*Yb which is energetically close to the 5^2P_{1/2} state of Rb is coupled by a strong laser field to a vibrational level in the ground state of RbYb and probed by a weak probe laser field. The induced Autler-Townes splittings in the photoassociation spectra allow us to determine relative Franck-Condon factors of molecular transitions in RbYb.

  14. Laser spectroscopy and cooling of Yb+ ions on a deep-UV transition

    CERN Document Server

    Meyer, Hendrik M; Ratschbacher, Lothar; Zipkes, Christoph; Köhl, Michael

    2011-01-01

    We perform laser spectroscopy of Yb+ ions on the 4f14 6s 2S_{1/2} - 4f13 5d 6s 3D[3/2]_{1/2} transition at 297 nm. The frequency measurements for 170Yb+, 172Yb+, 174Yb+, and 176Yb+ reveal the specific mass shift as well as the field shifts. In addition, we demonstrate laser cooling of Yb+ ions using this transition and show that light at 297 nm can be used as the second step in the photoionization of neutral Yb atoms.

  15. Diode laser spectroscopy of methyl chloride overtones at 850-860 nm

    Science.gov (United States)

    Lucchesini, A.; Gozzini, S.

    2016-01-01

    By using a tunable diode laser (TDL) spectrometer 156 CH3Cl overtone absorption lines have been detected in the range between 11,590 and 11,760 cm-1 (8500-8625 Å). Their strengths range around 10-26 -10-27 cm / molecule and have been measured by utilizing commercial AlGaAs/GaAs laser diodes through the wavelength modulation spectroscopy (WMS) and the 2nd harmonic (2f) detection techniques. For one line the self-broadening coefficient has been obtained.

  16. Double-pulse standoff laser-induced breakdown spectroscopy for versatile hazardous materials detection

    Energy Technology Data Exchange (ETDEWEB)

    Gottfried, Jennifer L. [U.S. Army Research Laboratory, AMSRD-ARL-WM-BD, Aberdeen Proving Ground, MD, 21005-5069 (United States)], E-mail: jennifer.gottfried@arl.army.mil; De Lucia, Frank C.; Munson, Chase A.; Miziolek, Andrzej W. [U.S. Army Research Laboratory, AMSRD-ARL-WM-BD, Aberdeen Proving Ground, MD, 21005-5069 (United States)

    2007-12-15

    We have developed a double-pulse standoff laser-induced breakdown spectroscopy (ST-LIBS) system capable of detecting a variety of hazardous materials at tens of meters. The use of a double-pulse laser improves the sensitivity and selectivity of ST-LIBS, especially for the detection of energetic materials. In addition to various metallic and plastic materials, the system has been used to detect bulk explosives RDX and Composition-B, explosive residues, biological species such as the anthrax surrogate Bacillus subtilis, and chemical warfare simulants at 20 m. We have also demonstrated the discrimination of explosive residues from various interferents on an aluminum substrate.

  17. A laser-generated plasma as a source of VUV continuum radiation for photoelectronic spectroscopy

    OpenAIRE

    Heckenkamp, Ch.; Heinzmann, Ulrich; Schönhense, G.; BURGESS.D.D; Thorne, A. P.; Wheaton, J. E. G.

    1981-01-01

    The feasibility of using laser-generated plasmas as VUV continuum sources for photoelectron spectroscopy has been demonstrated by measuring the spectral intensity distribution of the VUV continuum in the wavelength region from 79 to 43 nm by energy analysis of the photoelectrons ejected from argon atoms. The maximum photon flux obtained after reflection at a gold-coated spherical mirror was of the order of 10(11) photons nm(-1) per pulse at 50 nm for a laser energy of 830 mJ. The results show...

  18. Dual-Comb Coherent Raman Spectroscopy with Lasers of 1-GHz Pulse Repetition Frequency

    CERN Document Server

    Mohler, Kathrin J; Yan, Ming; Hänsch, Theodor W; Picqué, Nathalie

    2016-01-01

    We extend the technique of multiplex coherent Raman spectroscopy with two femtosecond mode-locked lasers to oscillators of a pulse repetition frequency of 1 GHz. We demonstrate spectra of liquids, which span 1100 cm$^{-1}$ of Raman shifts. At a resolution of 6 cm$^{-1}$, their measurement time may be as short as 5 microseconds for a refresh rate of 2 kHz. The waiting period between acquisitions is improved ten-fold compared to previous experiments with two lasers of 100-MHz repetition frequencies.

  19. Laser Spectroscopy of Vinyl Alcohol Embedded in Helium Droplets

    Science.gov (United States)

    Bunn, Hayley; Raston, Paul; Douberly, Gary E.

    2017-06-01

    Vinyl alcohol has two rotameric forms, known as syn- and anti-vinyl alcohol, where syn is the most stable. While both have been investigated by microwave and far-infrared spectroscopy, only the syn rotamer has been investigated by mid-infrared spectroscopy. This is due to the low anti rotamer population (15%) at room temperature, in addition to the closeness in proximity of the mid-infrared bands between the rotamers; this results in overlapping bands that are dominated by syn-vinyl alcohol absorptions. In this investigation we increase the anti-vinyl alcohol population to 40% by using a high temperature "pyrolysis" source, and eliminate the spectral overlap by recording the spectra at low temperature in helium nanodroplets. We observe a number of bands of both rotamers in the OH, CH, and CO stretching regions that display rotational substructure. A highlight of this work is the observation of a Fermi dyad in the OH stretching region of anti-vinyl alcohol. Anharmonic frequency calculations suggest that this is due to a near degeneracy of the OH stretching state (νb{1}) with a triple combination involving νb{7}, νb{8}, and νb{9}. M. Rodler, J. Mol. Spec. 114, 23 (1985);S. Saito, Chem. Phys. Lett. 42, 3 (1976) H. Bunn, R. Hudson, A. S. Gentleman, and P. L. Raston, ACS Earth Space Chem. DOI: 10.1021/acsearthspacechem.6b00008 (2017) D-L Joo, A. J. Merer, D. J. Clouthier, J. Mol. Spec. 197, 68 (1999)

  20. COMPLIS experiments: COllaboration for spectroscopy Measurements using a Pulsed Laser Ion Source

    Energy Technology Data Exchange (ETDEWEB)

    Sauvage, J. [IN2P3-CNRS, Institut de Physique Nucleaire (France); Boos, N. [Universitaet Mainz, Institut fuer Physik (Germany); Cabaret, L. [Laboratoire AimeCotton (France); Crawford, J.E. [McGill University, Physics Department (Canada); Duong, H.T. [Laboratoire AimeCotton (France); Genevey, J. [IN2P3-CNRS, Institut des Sciences Nucleaires (France); Girod, M. [Commissariat al' Energie Atomique, Service de Physique Nucleaire (France); Huber, G. [Universitaet Mainz, Institut fuer Physik (Germany); Ibrahim, F. [IN2P3-CNRS, Institut de Physique Nucleaire (France); Krieg, M. [Universitaet Mainz, Institut fuer Physik (Germany); Le Blanc, F. [IN2P3-CNRS, Institut de Physique Nucleaire (France); Lee, J.K.P. [McGill University, Physics Department (Canada); Libert, J. [Centre d' Etudes Nucleaires de Bordeaux Gradignan (France); Lunney, D.; Obert, J.; Oms, J. [IN2P3-CNRS, Institut de Physique Nucleaire (France); Peru, S. [Commissariat al' Energie Atomique, Service de Physique Nucleaire (France); Pinard, J. [Laboratoire AimeCotton (France); Putaux, J.C.; Roussiere, B. [IN2P3-CNRS, Institut de Physique Nucleaire (France)] (and others)

    2000-12-15

    Laser spectroscopy measurements have been carried out on very neutron-deficient isotopes of Au, Pt and Ir, produced as daughter elements from a Hg ISOLDE beam. For these transitional region nuclides, the hyperfine structure (HFS) and isotope shift (IS) were measured by Resonance Ionization Spectroscopy (RIS). Magnetic moments {mu}, spectroscopic quadrupole moments Q{sub s} and changes of the nuclear mean square charge radius {delta}along isotopic series have been extracted. For some results, a detailed comparison with theoretical predictions is presented.

  1. Spectroscopy of the hydrogen 1 S -3 S transition with chirped laser pulses

    Science.gov (United States)

    Yost, D. C.; Matveev, A.; Grinin, A.; Peters, E.; Maisenbacher, L.; Beyer, A.; Pohl, R.; Kolachevsky, N.; Khabarova, K.; Hänsch, T. W.; Udem, Th.

    2016-04-01

    We identify a systematic present in two-photon direct frequency comb spectroscopy (DFCS) which is a result of chirped laser pulses and is a manifestation of the first-order Doppler effect. We carefully analyze this systematic and propose methods for its mitigation within the context of our measurement of the hydrogen 1 S -3 S transition. We also report on our determination of the absolute frequency of this transition, which is comparable to a previous measurement using continuous-wave spectroscopy [O. Arnoult et al., Eur. Phys. J. D 60, 243 (2010), 10.1140/epjd/e2010-00249-6], but was obtained with a different experimental method.

  2. Laser Raman Spectroscopy with Different Excitation Sources and Extension to Surface Enhanced Raman Spectroscopy

    Directory of Open Access Journals (Sweden)

    Md. Wahadoszamen

    2015-01-01

    Full Text Available A dispersive Raman spectrometer was used with three different excitation sources (Argon-ion, He-Ne, and Diode lasers operating at 514.5 nm, 633 nm, and 782 nm, resp.. The system was employed to a variety of Raman active compounds. Many of the compounds exhibit very strong fluorescence while being excited with a laser emitting at UV-VIS region, hereby imposing severe limitation to the detection efficiency of the particular Raman system. The Raman system with variable excitation laser sources provided us with a desired flexibility toward the suppression of unwanted fluorescence signal. With this Raman system, we could detect and specify the different vibrational modes of various hazardous organic compounds and some typical dyes (both fluorescent and nonfluorescent. We then compared those results with the ones reported in literature and found the deviation within the range of ±2 cm−1, which indicates reasonable accuracy and usability of the Raman system. Then, the surface enhancement technique of Raman spectrum was employed to the present system. To this end, we used chemically prepared colloidal suspension of silver nanoparticles as substrate and Rhodamine 6G as probe. We could observe significant enhancement of Raman signal from Rhodamine 6G using the colloidal solution of silver nanoparticles the average magnitude of which is estimated to be 103.

  3. Laser plasma x-ray source for ultrafast time-resolved x-ray absorption spectroscopy.

    Science.gov (United States)

    Miaja-Avila, L; O'Neil, G C; Uhlig, J; Cromer, C L; Dowell, M L; Jimenez, R; Hoover, A S; Silverman, K L; Ullom, J N

    2015-03-01

    We describe a laser-driven x-ray plasma source designed for ultrafast x-ray absorption spectroscopy. The source is comprised of a 1 kHz, 20 W, femtosecond pulsed infrared laser and a water target. We present the x-ray spectra as a function of laser energy and pulse duration. Additionally, we investigate the plasma temperature and photon flux as we vary the laser energy. We obtain a 75 μm FWHM x-ray spot size, containing ∼10(6) photons/s, by focusing the produced x-rays with a polycapillary optic. Since the acquisition of x-ray absorption spectra requires the averaging of measurements from >10(7) laser pulses, we also present data on the source stability, including single pulse measurements of the x-ray yield and the x-ray spectral shape. In single pulse measurements, the x-ray flux has a measured standard deviation of 8%, where the laser pointing is the main cause of variability. Further, we show that the variability in x-ray spectral shape from single pulses is low, thus justifying the combining of x-rays obtained from different laser pulses into a single spectrum. Finally, we show a static x-ray absorption spectrum of a ferrioxalate solution as detected by a microcalorimeter array. Altogether, our results demonstrate that this water-jet based plasma source is a suitable candidate for laboratory-based time-resolved x-ray absorption spectroscopy experiments.

  4. Laser plasma x-ray source for ultrafast time-resolved x-ray absorption spectroscopy

    Directory of Open Access Journals (Sweden)

    L. Miaja-Avila

    2015-03-01

    Full Text Available We describe a laser-driven x-ray plasma source designed for ultrafast x-ray absorption spectroscopy. The source is comprised of a 1 kHz, 20 W, femtosecond pulsed infrared laser and a water target. We present the x-ray spectra as a function of laser energy and pulse duration. Additionally, we investigate the plasma temperature and photon flux as we vary the laser energy. We obtain a 75 μm FWHM x-ray spot size, containing ∼106 photons/s, by focusing the produced x-rays with a polycapillary optic. Since the acquisition of x-ray absorption spectra requires the averaging of measurements from >107 laser pulses, we also present data on the source stability, including single pulse measurements of the x-ray yield and the x-ray spectral shape. In single pulse measurements, the x-ray flux has a measured standard deviation of 8%, where the laser pointing is the main cause of variability. Further, we show that the variability in x-ray spectral shape from single pulses is low, thus justifying the combining of x-rays obtained from different laser pulses into a single spectrum. Finally, we show a static x-ray absorption spectrum of a ferrioxalate solution as detected by a microcalorimeter array. Altogether, our results demonstrate that this water-jet based plasma source is a suitable candidate for laboratory-based time-resolved x-ray absorption spectroscopy experiments.

  5. $\\beta$-delayed fission, laser spectroscopy and shape-coexistence studies with radioactive At beams

    CERN Multimedia

    We propose to study the $\\beta$-delayed fission, laser spectroscopy and radioactive decay of the newly available pure beams of neutron-deficient and neutron-rich astatine (Z=85) isotopes. The fission probability and the fission fragment distribution of the even-even isotopes $^{194,196}$Po following the $\\beta$-decay of the isotopes $^{194,196}$At will be studied with the Windmill setup. In-source laser spectroscopy will be performed on the entire astatine isotopic chain, using a combination of the Windmill setup, ISOLTRAP MR-ToF and ISOLDE Faraday. Radioactive decay data will be acquired at the Windmill setup throughout those studies and contribute to the global understanding of the phenomenon of shape coexistence in the neutron-deficient lead region.

  6. RFQ beam cooler and buncher for collinear laser spectroscopy of rare isotopes

    Science.gov (United States)

    Barquest, B. R.; Bollen, G.; Mantica, P. F.; Minamisono, K.; Ringle, R.; Schwarz, S.; Sumithrarachchi, C. S.

    2017-09-01

    A radiofrequency quadrupole (RFQ) ion beam cooler and buncher has been developed to deliver bunched beams with low transverse emittance, energy spread, and time spread to the BECOLA collinear laser spectroscopy system at the National Superconducting Cyclotron Laboratory (NSCL) at Michigan State University. The beam cooler and buncher contains new features which enhance performance, especially for high count rate beams, as well as simplifying construction, maintenance, and operation. The transverse emittance, energy spread, and time spread of the bunched beam, as well as buncher efficiency are reported, showcasing the capabilities of the BECOLA facility to perform collinear laser spectroscopy measurements with bunched rare isotope beams at NSCL and at the future Facility for Rare Isotope Beams (FRIB).

  7. Terahertz quantum-cascade lasers as high-power and wideband, gapless sources for spectroscopy.

    Science.gov (United States)

    Röben, Benjamin; Lü, Xiang; Hempel, Martin; Biermann, Klaus; Schrottke, Lutz; Grahn, Holger T

    2017-07-10

    Terahertz (THz) quantum-cascade lasers (QCLs) are powerful radiation sources for high-resolution and high-sensitivity spectroscopy with a discrete spectrum between 2 and 5 THz as well as a continuous coverage of several GHz. However, for many applications, a radiation source with a continuous coverage of a substantially larger frequency range is required. We employed a multi-mode THz QCL operated with a fast ramped injection current, which leads to a collective tuning of equally-spaced Fabry-Pérot laser modes exceeding their separation. A continuous coverage over 72 GHz at about 4.7 THz was achieved. We demonstrate that the QCL is superior to conventional sources used in Fourier transform infrared spectroscopy in terms of the signal-to-noise ratio as well as the dynamic range by one to two orders of magnitude. Our results pave the way for versatile THz spectroscopic systems with unprecedented resolution and sensitivity across a wide frequency range.

  8. Laser Calorimetry Spectroscopy for ppm-level Dissolved Gas Detection and Analysis.

    Science.gov (United States)

    K S, Nagapriya; Sinha, Shashank; R, Prashanth; Poonacha, Samhitha; Chaudhry, Gunaranjan; Bhattacharya, Anandaroop; Choudhury, Niloy; Mahalik, Saroj; Maity, Sandip

    2017-02-20

    In this paper we report a newly developed technique - laser calorimetry spectroscopy (LCS), which is a combination of laser absorption spectroscopy and calorimetry - for the detection of gases dissolved in liquids. The technique involves determination of concentration of a dissolved gas by irradiating the liquid with light of a wavelength where the gas absorbs, and measuring the temperature change caused by the absorbance. Conventionally, detection of dissolved gases with sufficient sensitivity and specificity was done by first extracting the gases from the liquid and then analyzing the gases using techniques such as gas chromatography. Using LCS, we have been able to detect ppm levels of dissolved gases without extracting them from the liquid. In this paper, we show the detection of dissolved acetylene in transformer oil in the mid infrared (MIR) wavelength (3021 nm) region.

  9. Laser Calorimetry Spectroscopy for ppm-level Dissolved Gas Detection and Analysis

    Science.gov (United States)

    K. S., Nagapriya; Sinha, Shashank; Prashanth, R.; Poonacha, Samhitha; Chaudhry, Gunaranjan; Bhattacharya, Anandaroop; Choudhury, Niloy; Mahalik, Saroj; Maity, Sandip

    2017-02-01

    In this paper we report a newly developed technique - laser calorimetry spectroscopy (LCS), which is a combination of laser absorption spectroscopy and calorimetry - for the detection of gases dissolved in liquids. The technique involves determination of concentration of a dissolved gas by irradiating the liquid with light of a wavelength where the gas absorbs, and measuring the temperature change caused by the absorbance. Conventionally, detection of dissolved gases with sufficient sensitivity and specificity was done by first extracting the gases from the liquid and then analyzing the gases using techniques such as gas chromatography. Using LCS, we have been able to detect ppm levels of dissolved gases without extracting them from the liquid. In this paper, we show the detection of dissolved acetylene in transformer oil in the mid infrared (MIR) wavelength (3021 nm) region.

  10. Laser Calorimetry Spectroscopy for ppm-level Dissolved Gas Detection and Analysis

    Science.gov (United States)

    K. S., Nagapriya; Sinha, Shashank; R., Prashanth; Poonacha, Samhitha; Chaudhry, Gunaranjan; Bhattacharya, Anandaroop; Choudhury, Niloy; Mahalik, Saroj; Maity, Sandip

    2017-01-01

    In this paper we report a newly developed technique – laser calorimetry spectroscopy (LCS), which is a combination of laser absorption spectroscopy and calorimetry - for the detection of gases dissolved in liquids. The technique involves determination of concentration of a dissolved gas by irradiating the liquid with light of a wavelength where the gas absorbs, and measuring the temperature change caused by the absorbance. Conventionally, detection of dissolved gases with sufficient sensitivity and specificity was done by first extracting the gases from the liquid and then analyzing the gases using techniques such as gas chromatography. Using LCS, we have been able to detect ppm levels of dissolved gases without extracting them from the liquid. In this paper, we show the detection of dissolved acetylene in transformer oil in the mid infrared (MIR) wavelength (3021 nm) region. PMID:28218304

  11. Consequences of Femtosecond Laser Filament Generation Conditions in Standoff Laser Induced Breakdown Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Harilal, Sivanandan S.; Yeak, J.; Brumfield, Brian E.; Phillips, Mark C.

    2016-08-08

    We investigate the role of femtosecond laser focusing conditions on ablation properties and its implications on analytical merits and standoff detection applications. Femtosecond laser pulses can be used for ablation either by tightly focusing or by using filaments generated during its propagation. We evaluated the persistence of atomic, and molecular emission features as well as time evolution of the fundamental properties (temperature and density) of ablation plumes generated using different methods.

  12. In-source laser spectroscopy of mercury isotopes

    CERN Multimedia

    This proposal follows on from the Letter of Intent, I-153. The neutron-deficient mercury isotopes are one of the prime examples of shape coexistence anywhere in the nuclear chart. Wide-ranging and complementary experimental and theoretical approaches have been used to investigate their structure over the last few years, however mean-square charge radii are unknown for isotopes with $\\textit{A}$ < 181. It is proposed to measure the isotope shift (IS) and hyperfine structure (HFS) of the 253-nm transition in $^{177-182}$Hg in an attempt to study the propagation of the famous odd-even staggering behaviour. At the other end of the chain, no information exists on the optical spectroscopy of Hg isotopes beyond the $\\textit{N}$ = 126 shell closure. There is a well-known "kink" in mean-square charge radii beyond this point in the even $\\textit{Z}$ $\\geq$ 82 elements. It is proposed to measure the IS of $^{207,208}$Hg in order to provide the first information on this effect below $\\textit{Z}$ = 82.

  13. Far infrared laser magnetic resonance spectroscopy of free radicals

    CERN Document Server

    Liu, Y

    1996-01-01

    determine the vibrational dependence of all the major molecular parameters. Several v=1 parameters have been determined for the first time. The results constitute the definitive parameters for the v=1 state of CF. Finally, the FIR LMR spectra of CH sub 2 Br, the first high resolution spectra of this radical in the gas phase, are described in Chapter 6. Due to the complexity of the spectra and the lack of spectroscopic information from other high resolution techniques, the CH sub 2 Br spectra have not yet been completely assigned and analysed. However, this study did allow the determination of the (B+C) value of the radical. In this dissertation both theoretical and experimental aspects of FIR LMR spectroscopy are discussed with particular emphasis on the radicals CF and CH sub 2 Br. Chapter 1 reviews the development and salient features of LMR. After a discussion of the basic concepts and principles of LMR in Chapter 2, Chapter 3 gives a detailed description of the Cambridge FIR LMR spectrometer used to searc...

  14. Laser fluorescence spectroscopy of zinc neutrals originating from laser-irradiated and ion-bombarded zinc sulfide and zinc surfaces

    Science.gov (United States)

    Arlinghaus, H. F.; Calaway, W. F.; Young, C. E.; Pellin, M. J.; Gruen, D. M.; Chase, L. L.

    Time-of-flight (TOF) measurements, employing high-resolution laser-induced fluorescence spectroscopy (LFS) as a probe, have been used to measure the yield and velocity distribution of Zn atoms ejected from a ZnS single crystal under irradiation by 308 nm photons. By comparison with the known ion sputtering yield for pure zinc, the absolute yield was determined to be 10 to the 10th power atoms/pulse at a laser fluence of 30 mJ/sq cm. The velocity distribution of the Zn atoms could be fitted by a Maxwell-Boltzmann distribution, having characteristic temperature of approx 2300 K. In addition, Doppler-shift techniques have been combined with TOF measurements in order to separate prompt from delayed emission of ablated atoms, as well as to probe possible molecular or cluster fragmentation. The results obtained suggest the possibility of molecular or cluster emission from ZnS.

  15. Self-absorption influence on the optical spectroscopy of zinc oxide laser produced plasma

    Energy Technology Data Exchange (ETDEWEB)

    De Posada, E; Arronte, M A; Ponce, L; Rodriguez, E; Flores, T [Centro de Investigacion en Ciencia Aplicada y TecnologIa Avanzada-Unidad Altamira, Tamaulipas (Mexico); Lunney, J G, E-mail: edeposada@ipn.mx [School of Physics, Trinity College Dublin (Ireland)

    2011-01-01

    Optical spectroscopy is used to study the laser ablation process of ZnO targets. It is demonstrated that even if Partial Local Thermal Equilibrium is present, self absorption process leads to a decrease of recorded lines emission intensities and have to be taken into account to obtain correct values of such parameters. It is presented a method that combines results of both Langmuir probe technique and Anisimov model to obtain correct values of plasma parameters.

  16. Quasi zero-background tunable diode laser absorption spectroscopy employing a balanced Michelson interferometer.

    Science.gov (United States)

    Guan, Zuguang; Lewander, Märta; Svanberg, Sune

    2008-12-22

    Tunable diode laser spectroscopy (TDLS) normally observes small fractional absorptive reductions in the light flux. We show, that instead a signal increase on a zero background can be obtained. A Michelson interferometer, which is initially balanced out in destructive interference, is perturbed by gas absorption in one of its arms. Both theoretical analysis and experimental demonstration show that the proposed zero-background TDLS can improve the achievable signal-to-noise ratio.

  17. Shell structure and level migrations in zinc studied using collinear laser spectroscopy

    CERN Multimedia

    Tungate, G; De rydt, M A E; Flanagan, K; Rajabali, M M; Hammen, M; Blaum, K; Froemmgen, N E; Kowalska, M; Campbell, P; Neugart, R; Kreim, K D; Stroke, H H; Krieger, A R; Procter, T J

    We propose to perform collinear laser spectroscopy of zinc isotopes to measure the nuclear spin, magnetic dipole moment, electric quadrupole moment and mean-square charge radius. The yield database indicates that measurements of the isotopes $^{60-81}$Zn will be feasible. These measurements will cross the N = 50 shell closure and provide nuclear moments in a region where an inversion of ground-state spin has been identified in neighbouring chains.

  18. Breath air measurement using wide-band frequency tuning IR laser photo-acoustic spectroscopy

    Science.gov (United States)

    Kistenev, Yury V.; Borisov, Alexey V.; Kuzmin, Dmitry A.; Bulanova, Anna A.; Boyko, Andrey A.; Kostyukova, Nadezhda Y.; Karapuzikov, Alexey A.

    2016-03-01

    The results of measuring of biomarkers in breath air of patients with broncho-pulmonary diseases using wide-band frequency tuning IR laser photo-acoustic spectroscopy and the methods of data mining are presented. We will discuss experimental equipment and various methods of intellectual analysis of the experimental spectra in context of above task. The work was carried out with partial financial support of the FCPIR contract No 14.578.21.0082 (ID RFMEFI57814X0082).

  19. Laser assisted nuclear decay spectroscopy: A new method for studying neutron-deficient francium

    CERN Document Server

    Lynch, Kara Marie

    2015-01-01

    Radioactive decay studies of rare isotopes produced at radioactive ion beam facilities have often been hindered by the presence of isobaric and isomeric contamination. The Collinear Resonance Ionization Spectroscopy (CRIS) experiment at ISOLDE, CERN uses laser radiation to stepwise excite and ionize an atomic beam in a particular isomeric state. Deflection of this selectively ionized beam of exotic nuclei, from the remaining neutral contaminants, allows ultra-sensitive detection of rare isotopes and nuclear structure measurements in background-free conditions.\

  20. Determining spatial sodium distribution in fresh and aged bread using laser-induced breakdown spectroscopy

    NARCIS (Netherlands)

    Scholtes-Timmerman, M.; Heddes, C.; Noort, M.W.J.; Veen, S. van

    2013-01-01

    A fast and easy-to-use method using laser-induced breakdown spectroscopy (LIBS) was set up to determine Na (sodium) distribution in baked bread. Standard bread was made using a standard recipe and the amount of salt added was 0, 0.5, 1, 2, 4, 10, 15 and 20g corresponding to 0, 0.25, 0.5, 1.0, 2.0, 5

  1. Laser spectroscopy of tin and cadmium: across N=82 and closing in on N=50

    CERN Multimedia

    We propose to study the isotopes of tin starting in proximity of N = 50 up to and beyond N = 82, as well as the "magic-plus-one" nuclei of cadmium at both shell closures. The objective is to determine model-independent properties of ground and isomeric states by high-resolution laser spectroscopy, which are essential for understanding the structure of nuclei and their astrophysical importance in this region of the nuclear chart.

  2. Determining spatial sodium distribution in fresh and aged bread using laser-induced breakdown spectroscopy

    NARCIS (Netherlands)

    Scholtes-Timmerman, M.; Heddes, C.; Noort, M.W.J.; Veen, S. van

    2013-01-01

    A fast and easy-to-use method using laser-induced breakdown spectroscopy (LIBS) was set up to determine Na (sodium) distribution in baked bread. Standard bread was made using a standard recipe and the amount of salt added was 0, 0.5, 1, 2, 4, 10, 15 and 20g corresponding to 0, 0.25, 0.5, 1.0, 2.0,

  3. Quantitative analysis of pathological nails using laser-induced breakdown spectroscopy (LIBS) technique.

    Science.gov (United States)

    Hamzaoui, S; Khleifia, R; Jaïdane, N; Ben Lakhdar, Z

    2011-01-01

    Laser-induced breakdown spectroscopy (LIBS) has been used as a potential method for simultaneous measurement of the elements Ca, Na, and K, for normal and pathological nails. We compared the measured LIBS spectra of these elements for normal and pathological nails. The B²∑+ --> X²∑+ violet band emission spectrum of CN was used for the estimation of the transient temperature of the plasma plume and consequently of the sample surface considering thermodynamic equilibrium.

  4. Improved algorithm for elemental analysis by laser-induced breakdown spectroscopy.

    Science.gov (United States)

    Kumar, Prashant; Subramanian, K P; Kumar, Ajai; Singh, R K

    2013-07-20

    We propose a calibration-free algorithm for retrieval of elemental concentrations using laser-induced breakdown spectroscopy. This is a simple and improved version of other ratio-based algorithms as it needs only one trial parameter to estimate all other concentrations. The present algorithm has been used to estimate the composition of a brass sample, and the results agree within 1% with electron probe microanalyzer measurements.

  5. Combined laser induced ignition and plasma spectroscopy: Fundamentals and application to a hydrogen-air combustor

    Energy Technology Data Exchange (ETDEWEB)

    Zimmer, L. [Aeroengine Technology Center, Japan Aerospace Exploration Agency, 7-44-1 Jindaiji-Higashi Chofu, 182-8522 Tokyo (Japan)], E-mail: laurent.zimmer@em2c.ecp.fr; Okai, K. [Aeroengine Technology Center, Japan Aerospace Exploration Agency, 7-44-1 Jindaiji-Higashi Chofu, 182-8522 Tokyo (Japan)], E-mail: okai@chofu.jaxa.jp; Kurosawa, Y. [Clean engine team, Japan Aerospace Exploration Agency, 7-44-1 Jindaiji-Higashi Chofu, 182-8522 Tokyo (Japan)], E-mail: kuro@chofu.jaxa.jp

    2007-12-15

    Combined Laser Induced Ignition and Plasma Spectroscopy (LI2PS) has the potential to give the exact local composition of a mixture at the ignition point and at the ignition time. However, as different laser energies are required to ignite a particular mixture as function of space, the typical approach using two power meters to calibrate the plasma spectroscopy measurement is not well suited. Furthermore, LI2PS requires single shot measurements and therefore high accuracy. In this paper, a novel calibration scheme is presented for application of Laser Induced Plasma Spectroscopy (LIPS) to gaseous analyses. Numerical simulations of air spectra are used to show that species emission can be used directly from the broadband spectra to determine the plasma conditions. The ratio of nitrogen emission around 744 nm and around 870 nm is found to be a sensitive indication of temperature in the emission ranging from 700 to 890 nm. Comparisons with experimental spectra show identical tendencies and validate the findings of the simulations. This approach is used in a partially-premixed hydrogen-air burner. First, helium is used instead of hydrogen. After an explanation of timing issue related to LIPS, it is shown that the calibration required depends only on nitrogen excitation and nitrogen-hydrogen ratio, without the need to know the deposited power. Measurements of the fuel distribution as function of injection momentum and spatial localization are reported. To illustrate the use of such a single shot approach, combined laser ignition and plasma spectroscopy is proposed. In this case, the calibration is based on hydrogen excitation and hydrogen-oxygen and hydrogen-nitrogen ratio. Results obtained with LI2PS show that ignition is successful only for high power and relatively high hydrogen concentration compared to the local mean. It is expected that LI2PS will become an important tool when dealing with partially-premixed or diffusion flame ignition.

  6. Analysis Si/Al ratio in zeolites type FAU by laser induced breakdown spectroscopy (LIBS)

    Science.gov (United States)

    Contreras, W. A.; Cabanzo, R.; Mejía-Ospino, E.

    2011-01-01

    In this work, Laser Induced Breakdown Spectroscopy (LIBS) is used to determine the Si/Al ratio of Zeolite type Y. The catalytic activity of zeolite is strongly dependent of the Si/Al ratio. We have used Si lines in the spectral region between 245-265 nm to determine temperature of the plasma generated on pelletized sample of zeolite, and stoichiometry relation between Si and Al.

  7. Pulsed-laser Pumped Photothermal Deflection Spectroscopy for Liquid Thermal Diffusivity Measurement

    Institute of Scientific and Technical Information of China (English)

    XIAO Liantuan; LI Changyong; ZHANG Linjie; ZHAO Yanting; JIA Suotang; ZHOU Guosheng

    2000-01-01

    The pulsed-laser pumped photothermal deflection spectroscopy (PPDS) is applied to measure liquid thermal diffusivity in a modified collinear configuration. Here the pulsed beam is regarded as in the form of a Dirac delta function. The experiment setup used is described. Measurement result for the thermal diffusivity of a liquid sample(magnta/ethanol saturated solution) is reported. The measurement error is less than 3%.

  8. Analysis of Frozen Sulfate and Chloride Salt Solutions Using Laser-induced Breakdown Spectroscopy Under Martian Conditions

    Science.gov (United States)

    Schröder, S.; Pavlov, S. G.; Hübers, H.-W.; Rauschenbach, I.; Jessberger, E. K.

    2010-03-01

    We showed the feasibility of laser-induced breakdown spectroscopy to analyze different frozen salt solutions under martian conditions. We focused on chloride and sulphate salts which were found on Mars and could lower the freezing point of water.

  9. Novel nuclear laser spectroscopy method using superfluid helium for measurement of spins and moments of exotic nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Furukawa, Takeshi, E-mail: takeshi@tmu.ac.jp [Department of Physics, Tokyo Metropolitan University, 1-1 Minami-Osawa, Hachioji, Tokyo 192-0397 (Japan); RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Wakui, Takashi [Cyclotron and Radioisotope Center, Tohoku University, 6-3 Aoba, Aramaki, Aoba, Sendai, Miyagi 980-8578 (Japan); Yang, Xiaofei [RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); School of Physics, Peking University, Chengfu Road, Haidian District, Beijing 100871 (China); Fujita, Tomomi [Department of Physics, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043 (Japan); Imamura, Kei; Yamaguchi, Yasuhiro [Department of Physics, Meiji University, 1-1-1 Higashi-Mita, Tama, Kawasaki, Kanagawa 214-8571 (Japan); Tetsuka, Hiroki; Tsutsui, Yoshiki [Department of Physics, Tokyo Gakugei University, 4-1-1 Nukuikitamachi, Koganei, Tokyo 184-8501,Japan (Japan); Mitsuya, Yosuke [Department of Physics, Meiji University, 1-1-1 Higashi-Mita, Tama, Kawasaki, Kanagawa 214-8571 (Japan); Ichikawa, Yuichi [RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Department of Physics, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro, Tokyo 152-8551 (Japan); Ishibashi, Yoko [RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Department of Physics, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8577 (Japan); Yoshida, Naoki; Shirai, Hazuki [RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Department of Physics, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro, Tokyo 152-8551 (Japan); Ebara, Yuta; Hayasaka, Miki [Department of Physics, Tokyo Gakugei University, 4-1-1 Nukuikitamachi, Koganei, Tokyo 184-8501,Japan (Japan); Arai, Shino; Muramoto, Sosuke [Department of Physics, Meiji University, 1-1-1 Higashi-Mita, Tama, Kawasaki, Kanagawa 214-8571 (Japan); and others

    2013-12-15

    Highlights: • Development of a novel nuclear laser spectroscopy method using superfluid helium. • Observation of the Zeeman resonance with the {sup 85}Rb beam introduced into helium. • Demonstration of deducing the nuclear spins from the observed resonance spectrum. -- Abstract: We have been developing a novel nuclear laser spectroscopy method “OROCHI” for determining spins and moments of exotic radioisotopes. In this method, we use superfluid helium as a stopping material of energetic radioisotope beams and then stopped radioisotope atoms are subjected to in situ laser spectroscopy in superfluid helium. To confirm the feasibility of this method for rare radioisotopes, we carried out a test experiment using a {sup 85}Rb beam. In this experiment, we have successfully measured the Zeeman resonance signals from the {sup 85}Rb atoms stopped in superfluid helium by laser-RF double resonance spectroscopy. This method is efficient for the measurement of spins and moments of more exotic nuclei.

  10. The differentiation of oral soft- and hard tissues using laser induced breakdown spectroscopy - a prospect for tissue specific laser surgery.

    Science.gov (United States)

    Rohde, Maximilian; Mehari, Fanuel; Klämpfl, Florian; Adler, Werner; Neukam, Friedrich-Wilhelm; Schmidt, Michael; Stelzle, Florian

    2016-11-22

    Compared to conventional techniques, Laser surgery procedures provide a number of advantages, but may be associated with an increased risk of iatrogenic damage to important anatomical structures. The type of tissue ablated in the focus spot is unknown. Laser-Induced Breakdown-Spectroscopy (LIBS) has the potential to gain information about the type of material that is being ablated by the laser beam. This may form the basis for tissue selective laser surgery. In the present study, 7 different porcine tissues (cortical and cancellous bone, nerve, mucosa, enamel, dentine and pulp) from 6 animals were analyzed for their qualitative and semiquantitative molecular composition using LIBS. The so gathered data was used to first differentiate between the soft- and hard-tissues using a Calcium-Carbon emission based classifier. The tissues were then further classified using emission-ratio based analysis, principal component analysis (PCA) and linear discriminant analysis (LDA). The relatively higher concentration of Calcium in the hard tissues allows for an accurate first differentiation of soft- and hard tissues (100% sensitivity and specificity). The ratio based statistical differentiation approach yields results in the range from 65% (enamel-dentine pair) to 100% (nerve-pulp, cancellous bone-dentine, cancellous bone-enamel pairs) sensitivity and specificity. Experimental LIBS measuring setup. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Nanometer-film analysis by the laser-induced breakdown spectroscopy method: the effects of laser focus to sample distance.

    Science.gov (United States)

    Sun, Yuxiang; Zhong, Shilei; Shan, Fukai; Lu, Yuan; Sun, Xin; Liu, Zhe; Sheng, Pengpeng

    2015-05-20

    In order to develop a method to analyze metal elements in thin-film samples rapidly, directly and without sample preparation, and to understand the mechanism of laser-film interaction and plasma formation and evolution, a laboratory laser-induced breakdown spectroscopy system was established recently for nanometer-film analysis. ZrO(2) films prepared on silicon chips by a sol-gel process were employed in the following experiment and their thickness was about 40 nm. By the initial investigation that we carried out, the stability of this system was verified and the relative standard deviation of the target peak was found to be lower than 1.6% with the help of a position system. The influences of different experimental parameters, such as laser energy, laser focus to sample distance (LFTSD) settings, and gate delay, were studied under conditions of room temperature and atmospheric pressure. The experimental results show that the LFTSD was one of the most important parameters for plasma formation and spectral collection in comparison with other parameters by means of plasma spectra and images. So the effects of the LFTSD on the spectra, plasma evolution, and craters are specially discussed in this paper. At last, we calculated the plasma temperature and electron density under optimal parameters for quantitative analysis. The result shows that the established system is available for qualitative and quantitative analysis of films under conditions of single pulse and low ablation energy.

  12. Boosting persistence time of laser-induced plasma by electric arc discharge for optical emission spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Eschlböck-Fuchs, S., E-mail: simon.eschlboeck-fuchs@jku.at [Christian Doppler Laboratory for Laser-Assisted Diagnostics, Institute of Applied Physics, Johannes Kepler University Linz, A-4040 Linz (Austria); Kolmhofer, P.J.; Bodea, M.A.; Hechenberger, J.G.; Huber, N. [Christian Doppler Laboratory for Laser-Assisted Diagnostics, Institute of Applied Physics, Johannes Kepler University Linz, A-4040 Linz (Austria); Rössler, R. [voestalpine Stahl GmbH, A-4031 Linz (Austria); Pedarnig, J.D., E-mail: johannes.pedarnig@jku.at [Christian Doppler Laboratory for Laser-Assisted Diagnostics, Institute of Applied Physics, Johannes Kepler University Linz, A-4040 Linz (Austria)

    2015-07-01

    Plasma induced by nanosecond laser ablation is re-excited by a pulsed electric discharge and the parameters and optical emission of the plasma are measured. The discharge is a low-voltage and high-current electric arc that is triggered by the laser-induced plasma and slowly decaying with time. The optical emission of such combined plasma lasts up to several milliseconds which is much longer than without re-excitation (μs range). The emission spectra of re-excited plasma measured on different sample materials show higher line intensities than spectra measured by conventional laser-induced breakdown spectroscopy (LIBS). Moreover, emission lines of fluorine (spectral range 683–691 nm) and sulfur (range 520–550 nm) not detected by conventional LIBS become easily detectable with the combined plasma. The concentration of major components in metallurgical slags, as determined by calibration-free LIBS, agrees very well to the reference data evaluating the spectra taken from re-excited plasma. - Highlights: • Persistence time of laser-induced plasma in air is increased from ~ 10 μs to ~ 1 ms. • Laser-induced plasma triggers an electric arc discharge that boosts the plasma. • The combined laser-arc plasma is in LTE state over very long time (ms range). • CF-LIBS method delivers accurate results evaluating spectra of combined plasma. • Emission from S and F, not detected by LIBS, is detected with combined plasma.

  13. Progress of laser ablation for accelerator mass spectroscopy at ATLAS utilizing an ECRIS

    Science.gov (United States)

    Scott, R.; Palchan, T.; Pardo, R.; Vondrasek, R.; Kondev, F.; Nusair, O.; Peters, C.; Paul, M.; Bauder, W.; Collon, P.

    2014-02-01

    Beams of ions from the laser ablation method of solid materials into an electron cyclotron resonance ion source (ECRIS) plasma have been used for the first time in experiments at ATLAS. Initial accelerator mass spectroscopy experiments using laser ablation for actinides and samarium have been performed. Initial results of coupling the laser system to the ECR source have guided us in making a number of changes to the original design. The point of laser impact has been moved off axis from the center of the ECR injection side. Motor control of the laser positioning mirror has been replaced with a faster and more reliable piezo-electric system, and different raster scan patterns have been tested. The use of the laser system in conjunction with a multi-sample changer has been implemented. Two major problems that are being confronted at this time are beam stability and total beam intensity. The status of the development will be presented and ideas for further improvements will be discussed.

  14. Approaching the ppb detection limits for copper in water using laser induced breakdown spectroscopy

    Science.gov (United States)

    Tawfik, Walid; Sawaf, Sausan

    2014-05-01

    Copper concentrations in drinking-water is very important to be monitored which can cause cancer if it exceed about 10 mg/liter. In the present work, we have developed a simple, low laser power method to improve the detection limits of laser induced plasma spectroscopy LIBS for copper in aqueous solutions with different concentrations. In this method a medium density fiberboard (MDF) wood have been used as a substrate that absorbs the liquid sample to transform laser liquid interaction to laser solid interaction. Using the fundamental wavelength of Nd:YAG laser, the constructed plasma emissions were monitored for elemental analysis. The signal-to-noise ratio SNR was optimized using low laser fluence of 32 J cm-2, and detector (CDD camera) gate delay of 0.5 μs. Both the electron temperature and density of the induced plasma were determined using Boltzmann plot and the FWHM of the Cu at 324.7 nm, respectively. The plasma temperature was found to be 1.197 eV, while the plasma density was about 1.66 x 1019 cm-3. The detection limits for Cu at 324.7 nm is found to be 131 ppb comparable to the results by others using complicated system.

  15. Laser speckle reduction techniques for mid-infrared microscopy and stand-off spectroscopy

    Science.gov (United States)

    Furstenberg, Robert; Kendziora, Christopher A.; Breshike, Christopher J.; Nguyen, Viet; McGill, R. Andrew

    2017-05-01

    Due to their high brightness, infrared (IR) lasers (such as tunable quantum cascade lasers, QCLLs) are very attractive illumination sources in both stand-off spectroscopy and micro-spectroscopy. In fact, they are the enabling device for trace-level spectroscopy. However, due to their high coherence as laser beams, QCLLs can cause speckle, especially when illuminating a rough surface. This is highly detrimental to the signal-to-noise ratio (SNR) of thee collected spectra and can easily negate the gains from using aa high brightness source. In most cases, speckle reduction is performed at the expense of optical power. In this paper, we examine several speckle reduction approaches and evaluate them for their ability to reduce speckle contrast while at the same time preserving aa high optical throughput. We analyze multi-mode fibers, integrating spheres, and stationary and moving diffusers for their speckle reduction potential. Speckle-contrast is measured directly by acquiring beam profiles of the illumination beam or, indirectly, by observing speckle formation from illuminating a rough surface (e.g. Infragold® coated surface) with an IR micro-bolometer camera. We also report on a novel speckle-reducing device with increased optical throughput. We characterize speckle contrast reduction from spatial, temporal and wavelength averaging for both CWW and pulsed QCLs. Examples of effect of speckle-reduction on hyperspectral images in both standoff and microscopy configurations are given.

  16. [Analysis of astaxanthin in Phaffia rhodozyma using laser tweezers raman spectroscopy].

    Science.gov (United States)

    Wang, Xue; Sun, Mei-Juan; Liu, Jun-Xian; Deng, Yang-Ge; Mo, Yu-Xiang; Tao, Zhan-Hua

    2012-09-01

    In the present paper, a method was established based on laser tweezer Raman spectroscopy for rapid quantification of astaxanthin in Phaffia rhodozyma cells. First, the Raman spectra of astaxanthin standard solution with different concentrations were determined and the standard curve for astaxanthin with the peak intensity at 1 520 cm- was plotted; And then the Phaffia yeast cells cultivated in different nitrogen source and carbon source medium were divided into two parts, one for the detection of Raman spectra, and the other for the determination of ultraviolet visible spectrophotometry; Finally the relationship between the two methods was analyzed. The correlation coefficient of standard curve for astaxanthin is 0.998 3. Comparing laser tweezers Raman spectroscopy method with traditional ultraviolet visible spectrophotometry in analyzing the content of astaxanthin in unit mass Phaffia rhodozyma and the yield of astaxanthin in unit volume fermentation broth of Phaffia rhodozyma, the authors found that the data obtained have good linear relationship. And the correlation coefficients are 0.917 7 and 0.905 4, respectively. Therefore, both methods have almost the same effect of measuement. But laser tweezers Raman spectroscopy method is more efficient in the quantitative analysis of astaxanthin in Phaffia rhodozyma cells.

  17. Picometer-resolution dual-comb spectroscopy with a free-running fibre laser

    CERN Document Server

    Zhao, Xin; Zhao, Bofeng; Li, Cui; Pan, Yingling; Liu, Ya; Yasui, Takeshi; Zheng, Zheng

    2016-01-01

    Dual-comb spectroscopy utilizes two sets of comb lines with slightly different comb-tooth-spacings, and optical spectral information is acquired by measuring the radio-frequency beat notes between the sets of comb lines. It holds the promise as a real-time, high-resolution analytical spectroscopy tool for a range of important applications. However, the stringent requirement on the coherence between comb lines from two separate lasers and the sophisticated control system to achieve that have confined the technology to the top metrology laboratories. By replacing electronics with the law of physics in lasers, a much simpler, dual-comb spectroscopy scheme is demonstrated here using just one dual-wavelength, passively mode-locked fiber laser. Dual-comb pulses with a repetition-frequency difference determined by the intracavity dispersion are shown to be robust against common-mode cavity drifts and noises. As sufficiently low relative linewidth is maintained between two sets of comb lines, capability to resolve pi...

  18. Frequency Stabilization of a 369 nm Diode Laser by Nonlinear Spectroscopy of Ytterbium Ions in a Discharge

    CERN Document Server

    Lee, Michael W; Marciniak, Christian; Biercuk, Michael J

    2014-01-01

    We demonstrate stabilisation of an ultraviolet diode laser via Doppler free spectroscopy of Ytterbium ions in a discharge. Our technique employs polarization spectroscopy, which produces a natural dispersive lineshape whose zero-crossing is largely immune to environmental drifts, making this signal an ideal absolute frequency reference for Yb$^+$ ion trapping experiments. We stabilise an external-cavity diode laser near 369 nm for cooling Yb$^+$ ions, using amplitude-modulated polarisation spectroscopy and a commercial PID feedback system. We achieve stable, low-drift locking with a standard deviation of measured laser frequency ~400 kHz over 10 minutes, limited by the instantaneous linewidth of the diode laser. These results and the simplicity of our optical setup makes our approach attractive for stabilization of laser sources in atomic-physics applications.

  19. Excited states in DNA strands investigated by ultrafast laser spectroscopy.

    Science.gov (United States)

    Chen, Jinquan; Zhang, Yuyuan; Kohler, Bern

    2015-01-01

    Ultrafast laser experiments on carefully selected DNA model compounds probe the effects of base stacking, base pairing, and structural disorder on excited electronic states formed by UV absorption in single and double DNA strands. Direct π-orbital overlap between two stacked bases in a dinucleotide or in a longer single strand creates new excited states that decay orders of magnitude more slowly than the generally subpicosecond excited states of monomeric bases. Half or more of all excited states in single strands decay in this manner. Ultrafast mid-IR transient absorption experiments reveal that the long-lived excited states in a number of model compounds are charge transfer states formed by interbase electron transfer, which subsequently decay by charge recombination. The lifetimes of the charge transfer states are surprisingly independent of how the stacked bases are oriented, but disruption of π-stacking, either by elevating temperature or by adding a denaturing co-solvent, completely eliminates this decay channel. Time-resolved emission measurements support the conclusion that these states are populated very rapidly from initial excitons. These experiments also reveal the existence of populations of emissive excited states that decay on the nanosecond time scale. The quantum yield of these states is very small for UVB/UVC excitation, but increases at UVA wavelengths. In double strands, hydrogen bonding between bases perturbs, but does not quench, the long-lived excited states. Kinetic isotope effects on the excited-state dynamics suggest that intrastrand electron transfer may couple to interstrand proton transfer. By revealing how structure and non-covalent interactions affect excited-state dynamics, on-going experimental and theoretical studies of excited states in DNA strands can advance understanding of fundamental photophysics in other nanoscale systems.

  20. Laser-Induced Breakdown Spectroscopy in open-path configuration for the analysis of distant objects

    Science.gov (United States)

    Sallé, B.; Mauchien, P.; Maurice, S.

    2007-08-01

    A review of recent results on stand-off Laser-Induced Breakdown Spectroscopy (LIBS) analysis and applications is presented. Stand-off LIBS was suggested for elemental analysis of materials located in environments where any physical access was not possible but optical access could be envisaged. This review only refers to the use of the open-path LIBS configuration in which the laser beam and the returning plasma light are transmitted through the atmosphere. It does not present the results obtained with a transportation of the laser pulses to the target through an optical fiber. Open-path stand-off LIBS has mainly been used with nanosecond laser pulses for solid sample analysis at distances of tens of meters. Liquid samples have also been analyzed at distances of a few meters. The distances achievable depend on many parameters including the laser characteristics (pulse energy and power, beam divergence, spatial profile) and the optical system used to focus the pulses at a distance. A large variety of laser focusing systems have been employed for stand-off analysis comprising refracting or reflecting telescope. Efficient collection of the plasma light is also needed to obtain analytically useful signals. For stand-off LIBS analysis, a lens or a mirror is required to increase the solid angle over which the plasma light can be collected. The light collection device can be either at an angle from the laser beam path or collinear with the optical axis of the system used to focus the laser pulses on the target surface. These different configurations have been used depending on the application such as rapid sorting of metal samples, identification of material in nuclear industry, process control and monitoring in metallurgical industry, applications in future planetary missions, detection of environmental contamination or cleaning of objects of cultural heritage. Recent stand-off analyses of metal samples have been reported using femtosecond laser pulses to extend LIBS

  1. Peltier cooled PbSe double-heterostructure lasers for IR-gas spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Preier, H.; Bleicher, M.; Riedel, W.; Pfeiffer, H.; Maier, H. (Allgemeine Elektricitaets-Gesellschaft AEG Telefunken, Frankfurt am Main (Germany, F.R.). Forschungsinstitut)

    1977-01-01

    PbS-PbSe-PbS double-heterostructure lasers have been pulse-operated at about 200 K mounted on 4 stage thermoelectric coolers. Emitting at a wavelength of about 5.5 ..mu..m they could be used for NO gas spectroscopy. Operation temperatures of up to 230 K have been achieved with structures consisting of n-type PbS substrates and epitaxial layers of n-type PbSe and Tl doped p-type PbS. The temperature dependence of the threshold current density and the emission wavelength of these DH-lasers was compared with PbSe-homojunction lasers. The use of a germanium etalon for a quick evaluation of the spectral quality of the emitted radiation is described.

  2. Characteristics of solid aerosols produced by optical catapulting studied by laser-induced breakdown spectroscopy

    Science.gov (United States)

    Fortes, F. J.; Laserna, J. J.

    2010-08-01

    Optical catapulting (OC) constitutes an effective method to transport small amounts of different materials in the form of a solid aerosol. In this report, laser-induced breakdown spectroscopy (LIBS) is used for the analysis of those aerosols produced by OC. For this purpose, materials were catapulted using a Q-switch Nd:YAG laser. A second Q-switch Nd:YAG laser was used for LIBS analysis of the ejected particles. Data processing of aerosols was conducted using conditional data analysis. Also, the standard deviation method was used for the qualitative identification of the ejected particles. Two modes of interaction in OC (OC with focused or defocused pulses) have been evaluated and discussed. LIBS demonstrates that the distribution (spreading) of the ejected particles along the propagation axis increased as a function of the interpulse delay time. The mass density and the thickness of the target also play an important role in OC-LIBS.

  3. Laser-induced breakdown spectroscopy: A versatile technique of elemental analysis and its applications

    CERN Document Server

    Rai, V N

    2014-01-01

    This paper reviews the state of art technology of laser induced breakdown spectroscopy (LIBS). Research on LIBS is gaining momentum in the field of instrumentation and data analysis technique due to its wide application in various field particularly in environmental monitoring and in industry. The main focus is on its miniaturization for field application and on increasing its sensitivity. The sensitivity of LIBS has been increased by confining the laser produced plasma using external magnetic field as well as using two successive laser pulse excitation of plasma. LIBS has capability for simultaneous multi element determination, localized microanalysis, surface analysis and has been used successfully for determination and identification of hazardous explosive and biological samples. Experimental findings of LIBS study in different applications have been discussed.

  4. White light scattering spectroscopy and electron microscopy of laser induced melting in single gold nanorods.

    Science.gov (United States)

    Zijlstra, Peter; Chon, James W M; Gu, Min

    2009-07-28

    We present the first measurements of laser induced melting and reshaping of single gold nanorods. Using a combination of white light scattering spectroscopy and electron microscopy we find a melting energy of 260 fJ for nanorods with an average size of 92 x 30 nm. Contrary to previous reports on ensembles of nanorods, this melting energy corresponds well to the theoretical prediction of 225 fJ. We observe a gradual shape change from a long and thin rod to a shorter and wider rod, which eventually collapses into a sphere when enough laser energy is deposited. We also observe that higher aspect ratio particles are thermodynamically less stable, leading to a greater reduction of the aspect ratio at lower laser pulse energy densities.

  5. Performance improvements in temperature reconstructions of 2-D tunable diode laser absorption spectroscopy (TDLAS)

    Science.gov (United States)

    Choi, Doo-Won; Jeon, Min-Gyu; Cho, Gyeong-Rae; Kamimoto, Takahiro; Deguchi, Yoshihiro; Doh, Deog-Hee

    2016-02-01

    Performance improvement was attained in data reconstructions of 2-dimensional tunable diode laser absorption spectroscopy (TDLAS). Multiplicative Algebraic Reconstruction Technique (MART) algorithm was adopted for data reconstruction. The data obtained in an experiment for the measurement of temperature and concentration fields of gas flows were used. The measurement theory is based upon the Beer-Lambert law, and the measurement system consists of a tunable laser, collimators, detectors, and an analyzer. Methane was used as a fuel for combustion with air in the Bunsen-type burner. The data used for the reconstruction are from the optical signals of 8-laser beams passed on a cross-section of the methane flame. The performances of MART algorithm in data reconstruction were validated and compared with those obtained by Algebraic Reconstruction Technique (ART) algorithm.

  6. A trap-based pulsed positron beam optimised for positronium laser spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Cooper, B. S., E-mail: ben.cooper.13@ucl.ac.uk; Alonso, A. M.; Deller, A.; Wall, T. E.; Cassidy, D. B. [Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT (United Kingdom)

    2015-10-15

    We describe a pulsed positron beam that is optimised for positronium (Ps) laser-spectroscopy experiments. The system is based on a two-stage Surko-type buffer gas trap that produces 4 ns wide pulses containing up to 5 × 10{sup 5} positrons at a rate of 0.5-10 Hz. By implanting positrons from the trap into a suitable target material, a dilute positronium gas with an initial density of the order of 10{sup 7} cm{sup −3} is created in vacuum. This is then probed with pulsed (ns) laser systems, where various Ps-laser interactions have been observed via changes in Ps annihilation rates using a fast gamma ray detector. We demonstrate the capabilities of the apparatus and detection methodology via the observation of Rydberg positronium atoms with principal quantum numbers ranging from 11 to 22 and the Stark broadening of the n = 2 → 11 transition in electric fields.

  7. The three dimensional laser induced temperature distribution in photo-thermal displacement spectroscopy

    CERN Document Server

    Soltanolkotabi, M

    2002-01-01

    In this paper we present a detailed theoretical treatment of 3-D temperature distribution induced by laser beam in photothermal displacement spectroscopy. We assume that a solid sample, which is deposited on a substrate and is in contact with a fluid, is irradiated by an intensity modulated cw laser source. By using a technique based on Green's function and integral transformations we find the explicit expression for temperature distribution function. This function which depends on the properties of the laser beam and optical and thermal properties of the sample, the substrate and the fluid, exhibits the characteristics of a damped thermal wave. Numerical analysis of the temperature distribution for a certain sample (GaAs) reveals that the behavior of thermal wave is not so sensitive with respect to the variation of the modulation frequency. On the other hand, we find that the temperature of the sample surface decreases with increasing modulation frequency because of the thermal inter tia of the sample. Furth...

  8. Laser-induced breakdown spectroscopy and chemometrics: a novel potential method to analyze wheat grains.

    Science.gov (United States)

    Martelli, Milena R; Brygo, François; Sadoudi, Abdelkrim; Delaporte, Philippe; Barron, Cécile

    2010-06-23

    Laser-induced breakdown spectroscopy (LIBS) has been widely used to evaluate the elemental composition (e.g., minerals or metal accumulation) on vegetal tissues. The main objective of this work was to differentiate wheat outer tissues during the grain ablation using LIBS and univariate/multivariate analysis. A high resolution spectrometer and a Nd:YAG laser (532 nm, 5 ns) was first used in order to easily identify atomic wheat emission lines. Then a pulsed excimer laser ArF (193 nm, 15 ns) and a compact fiber optic spectrometer was used to acquire LIBS spectral data from each pulse. Univariate and multivariate analyses (MW2D, PLS-DA) were carried out to provide more in depth information from the LIBS experiment. The number of pulses needed to ablate wheat tissues was successfully predicted by the supervised pattern recognition procedure. LIBS used in conjunction with multivariate analysis could be an interesting technique for rapid structural analysis of vegetal material.

  9. Bremsstrahlung and Line Spectroscopy of Warm Dense Aluminum Plasma Generated by EUV Free Electron Laser

    Energy Technology Data Exchange (ETDEWEB)

    Zastrau, U; Fortmann, C; Faustlin, R; Bornath, T; Cao, L F; Doppner, T; Dusterer, S; Forster, E; Glenzer, S H; Gregori, G; Holl, A; Laarmann, T; Lee, H; Meiwes-Broer, K; Przystawik, A; Radcliffe, P; Redmer, R; Reinholz, H; Ropke, G; Tiggesbaumker, J; Thiele, R; Truong, N X; Uschmann, I; Toleikis, S; Tschentscher, T; Wierling, A

    2008-03-07

    We report on the novel creation of a solid density aluminum plasma using free electron laser radiation at 13.5 nm wavelength. Ultrashort pulses of 30 fs duration and 47 {micro}J pulse energy were focused on a spot of 25 {micro}m diameter, yielding an intensity of 3 x 10{sup 14} W/cm{sup 2} on the bulk Al-target. The radiation emitted from the plasma was measured using a high resolution, high throughput EUV spectrometer. The analysis of both bremsstrahlung and line spectra results in an estimated electron temperature of (30 {+-} 10) eV, which is in very good agreement with radiation hydrodynamics simulations of the laser-target-interaction. This demonstrates the feasibility of exciting plasmas at warm dense matter conditions using EUV free electron lasers and their accurate characterization by EUV spectroscopy.

  10. Perspectives for neutron and gamma spectroscopy in high power laser driven experiments at ELI-NP

    Science.gov (United States)

    Negoita, F.; Gugiu, M.; Petrascu, H.; Petrone, C.; Pietreanu, D.; Fuchs, J.; Chen, S.; Higginson, D.; Vassura, L.; Hannachi, F.; Tarisien, M.; Versteegen, M.; Antici, P.; Balabanski, D.; Balascuta, S.; Cernaianu, M.; Dancus, I.; Gales, S.; Neagu, L.; Petcu, C.; Risca, M.; Toma, M.; Turcu, E.; Ursescu, D.

    2015-02-01

    The measurement of energy spectra of neutrons and gamma rays emitted by nuclei, together with charge particles spectroscopy, are the main tools for understanding nuclear phenomena occurring also in high power laser driven experiments. However, the large number of particles emitted in a very short time, in particular the strong X-rays flash produced in laser-target interaction, impose adaptation of technique currently used in nuclear physics experiment at accelerator based facilities. These aspects are discussed (Section 1) in the context of proposed studies at high power laser system of ELI-NP. Preliminary results from two experiments performed at Titan (LLNL) and ELFIE (LULI) facilities using plastic scintillators for neutron detection (Section 2) and LaBr3(Ce) scintillators for gamma detection (Section 3) are presented demonstrating the capabilities and the limitations of the employed methods. Possible improvements of these spectroscopic methods and their proposed implementation at ELI-NP will be discussed as well in the last section.

  11. Kinetic model of atomic and molecular emissions in laser-induced breakdown spectroscopy of organic compounds.

    Science.gov (United States)

    Ma, Qianli; Dagdigian, Paul J

    2011-07-01

    A kinetic model previously developed to predict the relative intensities of atomic emission lines in laser-induced breakdown spectroscopy has been extended to include processes related to CN and C(2) molecular emissions. Simulations with this model were performed to predict the relative excited-state populations. The results from the simulations are compared with experimentally determined excited-state populations from 1,064 nm laser irradiation of organic residues on aluminum foil. The model reasonably predicts the relative intensity of the molecular emissions. Significantly, the model reproduces the vastly different temporal profiles of the atomic and molecular emissions. The latter are found to extend to much longer times after the laser pulse, and this appears to be due to the increasing concentration of the molecules versus time. From the simulations, the important processes affecting the CN and C(2) concentrations are identified.

  12. Widely tunable Sampled Grating Distributed Bragg Reflector Quantum Cascade laser for gas spectroscopy applications

    Science.gov (United States)

    Diba, Abdou Salam

    Since the advent of semiconductor lasers, the development of tunable laser sources has been subject of many efforts in industry and academia arenas. This interest towards broadly tunable lasers is mainly due to the great promise they have in many applications ranging from telecommunication, to environmental science and homeland security, just to name a few. After the first demonstration of quantum cascade laser (QCL) in the early nineties, QCL has experienced a rapid development, so much so that QCLs are now the most reliable and efficient laser source in the Mid-IR range covering between 3 microm to 30 microm region of the electromagnetic spectrum. QCLs have almost all the desirable characteristics of a laser for spectroscopy applications such as narrow spectral linewidth ideal for high selectivity measurement, high power enabling high sensitivity sensing and more importantly they emit in the finger-print region of most of the trace gases and large molecules. The need for widely tunable QCLs is now more pressing than ever before. A single mode quantum cascade laser (QCL) such as a distributed feedback (DFB) QCL, is an ideal light source for gas sensing in the MIR wavelength range. Despite their performance and reliability, DFB QCLs are limited by their relatively narrow wavelength tuning range determined by the thermal rollover of the laser. An external cavity (EC) QCL, on the other hand, is a widely tunable laser source, and so far is the choice mid-infrared single frequency light sources for detecting multiple species/large molecules. However, EC QCLs can be complex, bulky and expensive. In the quest for finding alternative broadly wavelength tunable sources in the mid-infrared, many monolithic tunable QCLs are recently proposed and fabricated, including SG-DBR, DFB-Arrays, Slot-hole etc. and they are all of potentially of interest as a candidate for multi-gas sensing and monitoring applications, due to their large tuning range (>50 cm-1), and potentially low

  13. Coincidence spectroscopy of high-lying Rydberg states produced in strong laser fields

    Science.gov (United States)

    Larimian, Seyedreza; Erattupuzha, Sonia; Lemell, Christoph; Yoshida, Shuhei; Nagele, Stefan; Maurer, Raffael; Baltuška, Andrius; Burgdörfer, Joachim; Kitzler, Markus; Xie, Xinhua

    2016-09-01

    We demonstrate the detection of high-lying Rydberg states produced in strong laser fields with coincidence spectroscopy. Electron emission after the interaction of strong laser pulses with atoms and molecules is measured together with the parent ions in coincidence measurements. These electrons originate from high-lying Rydberg states with quantum numbers from n ˜20 up to n ≲120 formed by frustrated field ionization. Ionization rates are retrieved from the measured ionization signal of these Rydberg states. Simulations show that both tunneling ionization by a weak dc field and photoionization by blackbody radiation contribute to delayed electron emission on the nano- to microsecond scale. Furthermore, the dependence of the Rydberg-state production on the ellipticity of the driving laser field indicates that such high-lying Rydberg states are populated through electron recapture. The present experiment provides detailed quantitative information on Rydberg production in strong-field interaction.

  14. A new direct laser photo-induced fluorescence method coupled on-line with liquid chromatographic separation for the simultaneous determination of anilides pesticides.

    Science.gov (United States)

    Mbaye, O M A; Maroto, A; Gaye-Seye, M D; Stephan, L; Deschamps, L; Aaron, J J; Giamarchi, P

    2015-01-01

    A new direct laser photo-induced fluorescence high performance liquid chromatography (DL-PIF-HPLC) method is developed for the simultaneous determination of three anilide pesticides, namely carboxin, monalide and propanil. DL-PIF-HPLC uses a tunable Nd:YAG-OPO laser to obtain fluorescent photoproduct(s) and to simultaneously analyze their fluorescence in a short acquisition time with an intensified CCD camera, which improves the selectivity (by choosing the suitable excitation wavelength), increases the sensitivity (due to the high energy of the laser beam) and reduces the time of analysis, relative to the classical PIF methods. However, one of the main drawbacks of PIF methods is the presence of interferences with other compounds, such as other pesticides from the same group yielding similar fluorescent photoproducts, which reduces their selectivity. The analytical interest of DL-PIF-HPLC to avoid these interferences is demonstrated. The DL-PIF spectra, chromatographic conditions and analytical performances of DL-PIF-HPLC are presented for the simultaneous determination of three anilide pesticides. The calibration curves are linear over one order of magnitude and the limits of detection are in the ng mL(-1) range. The new DL-PIF-HPLC system has the advantage to combine the performances of both techniques, DL-PIF and liquid chromatography, and to improve the analysis selectivity.

  15. [On using tunable diode laser absorption spectroscopy to determine gas fluxes over cropland].

    Science.gov (United States)

    Tian, Yong-zhi; Liu, Jian-guo; Zhang, Yu-jun; Lu, Yi-huai; He, Ying

    2012-04-01

    Tunable diode laser absorption spectroscopy (TDLAS) is a compact, automated, high precision technique and fit for in-situ or field measurements. Two spectroscopy measurement systems, TDLAS and NDIR (non-dispersive infrared spectroscopy), were used to monitor trace gas emission over cropland at Fengqiu Agricultural Ecology Experimental Station for one month. The fluxes of carbon dioxide were estimated by flux-gradient and eddy covariance method, respectively. A footprint model was developed during experiment. Based on this model, the source areas of TDLAS and NDIR were investigated. The effects of different factors on the flux measurement were also analyzed. The authors concluded that the source areas for the two techniques are discrepant in most of the cases. The source areas increase with path length and detecting height. This result will help the installation of instruments.

  16. Wavelength modulation spectroscopy based on quasi-continuous-wave diode lasers

    Institute of Scientific and Technical Information of China (English)

    Rubin Qi; Zhenhui Du; Dongyu Gao; Jinyi Li; Kexin Xu

    2012-01-01

    A modified wavelength modulation spectroscopy (WMS) based on the self-heating effect of the tunable diode laser when driven in quasi-continuous-wave (QCW) mode is investigated.A near-infrared distributed feedback (DFB) diode laser working at the QCW mode is employed as the QCW light source,and CO2 is selected as the target gas.The characteristic of the QCW second harmonic (2f) line profile is analyzed through a comparison with that of the traditional CW WMS with the same system.A noise-equivalent absorbance of 3.2× 10-5 Hz-1/2 for CO2 at 1.58 μm is obtained with 18-m optical path.The QCW WMS lowers the dependence on lasers and expands selectivity,thus verifying the feasibility of the method.%A modified wavelength modulation spectroscopy (WMS) based on the self-heating effect of the tunable diode laser when driven in quasi-continuous-wave (QCW) mode is investigated. A near-infrared distributed feedback (DFB) diode laser working at the QCW mode is employed as the QCW light source, and CO2 is selected as the target gas. The characteristic of the QCW second harmonic (2f) line profile is analyzed through a comparison with that of the traditional CW WMS with the same system. A noise-equivalent absorbance of 3.2×l0-5 Hz-1/2 for CO2 at 1.58 μm is obtained with 18-m optical path. The QCW WMS lowers the dependence on lasers and expands selectivity, thus verifying the feasibility of the method.

  17. Laser systems for collinear spectroscopy and the charge radius of {sup 12}Be

    Energy Technology Data Exchange (ETDEWEB)

    Krieger, Andreas

    2012-03-30

    Collinear laser spectroscopy has been used to investigate the nuclear charge radii of shortlived medium- and heavy-Z nuclei for more than three decades. But it became only recently be applicable to low-Z nuclei. This region of the nuclear chart attracts attention because so-called ab-initio nuclear models, based on realistic nucleon-nucleon potentials, can only be applied to the lightest elements due to the rapidly increasing calculational demands with the number of nucleons. Furthermore, strong clusterization of atomic nuclei occurs and the encountered halo nuclei are presently subject of intense research. The isotopic chain of beryllium exhibits the prime example of a one-neutron halo nucleus, {sup 11}Be, and the two- or four-neutron halo nucleus {sup 14}Be. {sup 12}Be is a key isotope between these two exotic nuclei and particularly interesting because the nuclear shell model predicts a shell closure for the magic neutron number N = 8. In the course of this thesis, several frequency-stabilized laser systems for collinear laser spectroscopy have been developed. At TRIGA-SPEC a frequency-doubled diode laser system with a tapered amplifier and a frequency comb-stabilized titanium-sapphire laser with a frequency doubling stage are now available for the spectroscopy of refractory metals above molybdenum. They have already been used for test-experiments and commissioning of the TRIGA-LASER beamline. Furthermore, frequency-quadrupling of the Ti:Sa laser was demonstrated to expand the emitted wavelengths into the 200 nm region. At ISOLDE/CERN a frequency comb-stabilized and an iodine-stabilized dye laser were installed and applied for laser spectroscopy of {sup 9,10,11,12}Be{sup +}. The improved laser system and the development of a delayed photon-ion coincidence detection improved the sensitivity of the beryllium spectroscopy by more than two orders of magnitude and, thus, the previous measurements of {sup 7-11}Be could be extended for the first time to the short

  18. Measurement of Moments and Radii of Light Nuclei by Collinear Fast-Beam Laser Spectroscopy and $\\beta$-NMR Spectroscopy

    CERN Multimedia

    Marinova, K P

    2002-01-01

    Nuclear Moments and radii of light unstable isotopes are investigated by applying different high-sensitivity and high-resolution techniques based on collinear fast-beam laser spectroscopy. A study of nuclear structure in the sd shell is performed on neon isotopes in the extended chain of $^{17-28}$Ne, in particular on the proton-halo candidate $^{17}$Ne. Measurements of hyperfine structure and isotope shift have become possible by introducing an ultra-sensitive non-optical detection method which is based on optical pumping, state-selective collisional ionization and $\\beta$-activity counting. The small effect of nuclear radii on the optical isotope shifts of light elements requires very accurate measurements. The errors are dominated by uncertainties of the Doppler shifts which are conventionally determined from precisely measured acceleration voltages. These uncertainties are removed by measuring the beam energy with simultaneous excitation of two optical lines in parallel / antiparallel beam configuration. ...

  19. Wavelength dependence of laser induced breakdown spectroscopy (LIBS) on questioned document investigation.

    Science.gov (United States)

    Elsherbiny, Nany; Aied Nassef, O

    2015-07-01

    The fast and nearly non-destructive criteria of laser induced breakdown spectroscopy (LIBS) technique has been exploited for forensic purposes, specifically, document investigation. The dependence of the optical emission spectra of different black gel ink samples on the excitation laser wavelength, namely the visible wavelength at λ=532 nm and the IR wavelength at λ=1064 nm, was studied. The inks of thirty black gel-ink pens comprising ten brands were analyzed to determine the variation of the chemical composition of ink and to discriminate among them with minimum mass removal and minimum damage to the document's paper. Under the adopted experimental conditions, the ability of the visible LIBS to differentiate among the different ink samples was successful compared to IR LIBS at the same laser pulse energy (~25 mJ/pulse, laser fluence is ~1400J·cm(-2) for visible laser and ~1100J·cm(-2) for IR laser) which could be attributed to the IR absorption effects by the black ink. However, the visible LIBS produces deeper crater with respect to that produced by IR LIBS. Applying IR LIBS with higher pulse energy of ~87mJ (laser fluence is ~4100J·cm(-2)), identification and differentiation of the adopted samples was performed with producing a larger-diameter but superficial crater. The plasma parameters are discussed at the adopted experimental conditions. The results support the potential of LIBS technique using both the visible and IR lasers to be commercially developed for forensic document examination. Copyright © 2015 Forensic Science Society. Published by Elsevier Ireland Ltd. All rights reserved.

  20. Optical emission enhancement in laser-induced breakdown spectroscopy using micro-torches

    Science.gov (United States)

    Liu, L.; Huang, X.; Li, S.; Lu, Yao; Chen, K.; Lu, Y. F.

    2016-03-01

    A cost effective method for optical emission enhancement in laser-induced breakdown spectroscopy (LIBS) has been proposed in this research. The pulsed Nd:YAG laser with a wavelength of 532 nm was used for sample ablation and plasma generation. A cost effective commercial butane micro-torch was put parallel to the sample surface to generate a small flame above the surface. The laser-induced plasma expanded in the flame environment. The time-resolved optical emission intensity and signal-to-noise ratio (SNR) have been observed with and without micro torch. For laser with pulse energy of 20 mJ, the relationship between optical emission intensity and delay time indicates that signal intensities have been greatly enhanced in the initial several microseconds when using micro torch. The time-resolved study of signal-to-noise ratio shows that the maximum SNR occurs at the delay time of 2 μs. The laser energy effects on the enhancements of optical emission intensity and SNR have also been analyzed, which indicates that the enhancement factors are both delay time and laser energy dependent. The maximum enhancement factors for both optical emission intensity and SNR gradually decreases with the laser energy increase. The limits of detection (LODs) for aluminum (Al) and molybdenum (Mo) in steel have been estimated, which shows that the detection sensitivity has been improved by around 4 times. The LODs of Al and Mo have been reduced from 18 to 6 ppm and from 110 to 36 ppm in LIBS, respectively. The method of LIBS by a micro torch has been demonstrated to be a cost effective method for detection sensitivity improvement, especially in the situation of low laser pulse energy.

  1. Noise-cancelled, cavity-enhanced saturation laser spectroscopy for laser frequency stabilisation

    Energy Technology Data Exchange (ETDEWEB)

    Vine, Glenn de; McClelland, David E; Gray, Malcolm B [Centre for Gravitational Physics, Faculty of Science, Australian National University, Canberra, ACT 0200 (Australia)

    2006-03-02

    We employ a relatively simple experimental technique enabling mechanical-noise free, cavityenhanced spectroscopic measurements of an atomic transition and its hyperfine structure. We demonstrate this technique with the 532 nm frequency doubled output from a Nd:YAG laser and an iodine vapour cell. The resulting cavity-enhanced, noise-cancelled, iodine hyperfine error signal is used as a frequency reference with which we stabilise the frequency of the 1064nm Nd:YAG laser. Preliminary frequency stabilisation results are then presented.

  2. A Simple Laser Induced Breakdown Spectroscopy (LIBS) System for Use at Multiple Levels in the Undergraduate Chemistry Curriculum

    Science.gov (United States)

    Randall, David W.; Hayes, Ryan T.; Wong, Peter A.

    2013-01-01

    A LIBS (laser induced breakdown spectroscopy) spectrometer constructed by the instructor is reported for use in undergraduate analytical chemistry experiments. The modular spectrometer described here is based on commonly available components including a commercial Nd:YAG laser and a compact UV-vis spectrometer. The modular approach provides a…

  3. A Simple Laser Induced Breakdown Spectroscopy (LIBS) System for Use at Multiple Levels in the Undergraduate Chemistry Curriculum

    Science.gov (United States)

    Randall, David W.; Hayes, Ryan T.; Wong, Peter A.

    2013-01-01

    A LIBS (laser induced breakdown spectroscopy) spectrometer constructed by the instructor is reported for use in undergraduate analytical chemistry experiments. The modular spectrometer described here is based on commonly available components including a commercial Nd:YAG laser and a compact UV-vis spectrometer. The modular approach provides a…

  4. Temperature and Electron Density Determination on Laser-Induced Breakdown Spectroscopy (LIBS) Plasmas: A Physical Chemistry Experiment

    Science.gov (United States)

    Najarian, Maya L.; Chinni, Rosemarie C.

    2013-01-01

    This laboratory is designed for physical chemistry students to gain experience using laser-induced breakdown spectroscopy (LIBS) in understanding plasma diagnostics. LIBS uses a high-powered laser that is focused on the sample causing a plasma to form. The emission of this plasma is then spectrally resolved and detected. Temperature and electron…

  5. Temperature and Electron Density Determination on Laser-Induced Breakdown Spectroscopy (LIBS) Plasmas: A Physical Chemistry Experiment

    Science.gov (United States)

    Najarian, Maya L.; Chinni, Rosemarie C.

    2013-01-01

    This laboratory is designed for physical chemistry students to gain experience using laser-induced breakdown spectroscopy (LIBS) in understanding plasma diagnostics. LIBS uses a high-powered laser that is focused on the sample causing a plasma to form. The emission of this plasma is then spectrally resolved and detected. Temperature and electron…

  6. In situ diagnosis of pulsed UV laser surface ablation of tungsten carbide hardmetal by using laser-induced optical emission spectroscopy

    Science.gov (United States)

    Li, Tiejun; Lou, Qihong; Wei, Yunrong; Huang, Feng; Dong, Jingxing; Liu, Jingru

    2001-12-01

    Surface ablation of cobalt cemented tungsten carbide hardmetal with pulsed UV laser has been in situ diagnosed by using the technique of laser-induced optical emission spectroscopy. The dependence of emission intensity of cobalt lines on number of laser shots was investigated at laser fluence of 2.5 J/cm 2. As a comparison, the reliance of emission intensity of cobalt lines as a function of laser pulse number by using pure cobalt as ablation sample was also studied at the same laser condition. It was found that for surface ablation of tungsten carbide hardmetal at laser fluence of 2.5 J/cm 2, the intensities of cobalt lines fell off dramatically in the first 300 consecutive laser shots and then slowed down to a low stable level with even more shots. For surface ablation of pure cobalt at the same laser condition, the intensities of cobalt lines remained constant more or less even after 500 laser shots and then reduced very slowly with even more shots. It was concluded that selective evaporation of cobalt at this laser fluence should be responsible for the dramatic fall-off of cobalt lines with laser shots accumulation for surface ablation of tungsten carbide hardmetal. In contrast, for surface ablation of pure cobalt, the slow reduction of cobalt lines with pulse number accumulation should be due to the formation of laser-induced crater effect.

  7. Inactivation of Spores of Bacillus Species by Wet Heat: Studies on Single Spores Using Laser Tweezers Taman Spectroscopy

    Science.gov (United States)

    2013-02-01

    germination using phase contrast and fluorescence microscopy, Raman spectroscopy and optical tweezers, Nature Protocols , (04 2011): . doi: 05/11...multiple individual spores [ Nature Protocols , 6, 625 (2011)]. (1e) We developed a multiple-trap laser tweezers Raman spectroscopy (LTRS) array for

  8. Comparison of laser induced breakdown spectroscopy and spark induced breakdown spectroscopy for determination of mercury in soils

    Energy Technology Data Exchange (ETDEWEB)

    Srungaram, Pavan K.; Ayyalasomayajula, Krishna K.; Yu-Yueh, Fang; Singh, Jagdish P., E-mail: singh@icet.msstate.edu

    2013-09-01

    Mercury is a toxic element found throughout the environment. Elevated concentrations of mercury in soils are quite hazardous to plants growing in these soils and also the runoff of soils to nearby water bodies contaminates the water, endangering the flora and fauna of that region. This makes continuous monitoring of mercury very essential. This work compares two potential spectroscopic methods (laser induced breakdown spectroscopy (LIBS) and spark induced breakdown spectroscopy (SIBS)) at their optimum experimental conditions for mercury monitoring. For LIBS, pellets were prepared from soil samples of known concentration for generating a calibration curve while for SIBS, soil samples of known concentration were used in the powder form. The limits of detection (LODs) of Hg in soil were calculated from the Hg calibration curves. The LOD for mercury in soil calculated using LIBS and SIBS is 483 ppm and 20 ppm, respectively. The detection range for LIBS and SIBS is discussed. - Highlights: • We compared SIBS and LIBS for mercury (Hg) measurements in soil. • Hg 546.07 nm line was selected for both LIBS and SIBS measurements. • Limit of detection for Hg was found to be 20 ppm with SIBS and 483 ppm with LIBS.

  9. 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.

  10. Plasma diagnostics from self-absorbed doublet lines in laser-induced breakdown spectroscopy

    Science.gov (United States)

    D'Angelo, C. A.; Garcimuño, M.; Díaz Pace, D. M.; Bertuccelli, G.

    2015-10-01

    In this paper, a generalized approach is developed and applied for plasma characterization and quantitative purposes in laser-induced breakdown spectroscopy (LIBS) experiences by employing a selected pair of spectral lines belonging to the same multiplet. It is based on the comparison between experimental ratios of line parameters and the theoretical calculus obtained under the framework of a homogeneous plasma in local thermodynamic equilibrium. The applicability of the method was illustrated by using the atomic resonance transitions 279.55-280.27 nm of Mg II, which are usually detected in laser-induced plasma (LIP) during laser ablation of many kinds of targets. The laser induced plasmas were produced using a Nd:YAG laser from a pressed pellet of powdered calcium hydroxide with a concentration of 300 ppm of Mg. The experimental ratios for peak intensities, total intensities and Stark widths were obtained for different time windows and matched to the theoretical calculus. The temperature and the electron density of the plasma, as well as the Mg columnar density (the atom/ion concentration times the length of the plasma along the line-of-sight), were determined. The results were interpreted under the employed approach.

  11. Eye-safe infrared laser-induced breakdown spectroscopy (LIBS) emissions from energetic materials

    Science.gov (United States)

    Brown, Ei E.; Hömmerich, Uwe; Yang, Clayton C.; Jin, Feng; Trivedi, Sudhir B.; Samuels, Alan C.

    2016-05-01

    Laser-induced breakdown spectroscopy is a powerful diagnostic tool for detection of trace elements by monitoring the atomic and ionic emission from laser-induced plasmas. Besides elemental emissions from conventional UV-Vis LIBS, molecular LIBS emission signatures of the target compounds were observed in the long-wave infrared (LWIR) region in recent studies. Most current LIBS studies employ the fundamental Nd:YAG laser output at 1.064 μm, which has extremely low eye-damage threshold. In this work, comparative LWIR-LIBS emissions studies using traditional 1.064 μm pumping and eye-safe laser wavelength at 1.574 μm were performed on several energetic materials for applications in chemical, biological, and explosive (CBE) sensing. A Q-switched Nd: YAG laser operating at 1.064 μm and the 1.574 μm output of a pulsed Nd:YAG pumped Optical Parametric Oscillator were employed as the excitation sources. The investigated energetic materials were studied for the appearance of LWIR-LIBS emissions (4-12 μm) that are directly indicative of oxygenated breakdown products as well as partially dissociated and recombination molecular species. The observed molecular IR LIBS emission bands showed strong correlation with FTIR absorption spectra of the studied materials for 1.064 μm and 1.574 μm pump wavelengths.

  12. Laser induced breakdown spectroscopy based on single beam splitting and geometric configuration for effective signal enhancement.

    Science.gov (United States)

    Yang, Guang; Lin, Qingyu; Ding, Yu; Tian, Di; Duan, Yixiang

    2015-01-05

    A new laser induced breakdown spectroscopy (LIBS) based on single-beam-splitting (SBS) and proper optical geometric configuration has been initially explored in this work for effective signal enhancement. In order to improve the interaction efficiency of laser energy with the ablated material, a laser beam operated in pulse mode was divided into two streams to ablate/excite the target sample in different directions instead of the conventional one beam excitation in single pulse LIBS (SP-LIBS). In spatial configuration, the laser beam geometry plays an important role in the emission signal enhancement. Thus, an adjustable geometric configuration with variable incident angle between the two splitted laser beams was constructed for achieving maximum signal enhancement. With the optimized angles of 60° and 70° for Al and Cu atomic emission lines at 396.15 nm and 324.75 nm respectively, about 5.6- and 4.8-folds signal enhancements were achieved for aluminum alloy and copper alloy samples compared to SP-LIBS. Furthermore, the temporal analysis, in which the intensity of atomic lines in SP-LIBS decayed at least ten times faster than the SBS-LIBS, proved that the energy coupling efficiency of SBS-LIBS was significantly higher than that of SP-LIBS.

  13. Compositional Analysis of Aerosols Using Calibration-Free Laser-Induced Breakdown Spectroscopy.

    Science.gov (United States)

    Boudhib, Mohamed; Hermann, Jörg; Dutouquet, Christophe

    2016-04-05

    We demonstrate that the elemental composition of aerosols can be measured using laser-induced breakdown spectroscopy (LIBS) without any preliminary calibration with standard samples. Therefore, a nanosecond Nd:YAG laser beam was focused into a flux of helium charged with alumina aerosols of a few micrometers diameter. The emission spectrum of the laser-generated breakdown plasma was recorded with an echelle spectrometer coupled to a gated detector. The spectral features including emission from both the helium carrier gas and the Al2O3 aerosols were analyzed on the base of a partial local thermodynamic equilibrium. Thus, Boltzmann equilibrium distributions of population number densities were assumed for all plasma species except of helium atoms and ions. By analyzing spectra recorded for different delays between the laser pulse and the detector gate, it is shown that accurate composition measurements are only possible for delays ≤1 μs, when the electron density is large enough to ensure collisional equilibrium for the aerosol vapor species. The results are consistent with previous studies of calibration-free LIBS measurements of solid alumina and glass and promote compositional analysis of aerosols via laser-induced breakdown in helium.

  14. Laser Induced Breakdown Spectroscopy Based on Single Beam Splitting and Geometric Configuration for Effective Signal Enhancement

    Science.gov (United States)

    Yang, Guang; Lin, Qingyu; Ding, Yu; Tian, Di; Duan, Yixiang

    2015-01-01

    A new laser induced breakdown spectroscopy (LIBS) based on single-beam-splitting (SBS) and proper optical geometric configuration has been initially explored in this work for effective signal enhancement. In order to improve the interaction efficiency of laser energy with the ablated material, a laser beam operated in pulse mode was divided into two streams to ablate/excite the target sample in different directions instead of the conventional one beam excitation in single pulse LIBS (SP-LIBS). In spatial configuration, the laser beam geometry plays an important role in the emission signal enhancement. Thus, an adjustable geometric configuration with variable incident angle between the two splitted laser beams was constructed for achieving maximum signal enhancement. With the optimized angles of 60° and 70° for Al and Cu atomic emission lines at 396.15 nm and 324.75 nm respectively, about 5.6- and 4.8-folds signal enhancements were achieved for aluminum alloy and copper alloy samples compared to SP-LIBS. Furthermore, the temporal analysis, in which the intensity of atomic lines in SP-LIBS decayed at least ten times faster than the SBS-LIBS, proved that the energy coupling efficiency of SBS-LIBS was significantly higher than that of SP-LIBS. PMID:25557721

  15. High-resolution spectroscopy on the laser-cooling candidate La^{-}.

    Science.gov (United States)

    Jordan, E; Cerchiari, G; Fritzsche, S; Kellerbauer, A

    2015-09-11

    The bound-bound transition from the 5d^{2}6s^{2} ^{3}F_{2}^{e} ground state to the 5d6s^{2}6p ^{3}D_{1}^{o} excited state in negative lanthanum has been proposed as a candidate for laser cooling, which has not yet been achieved for negative ions. Anion laser cooling holds the potential to allow the production of ultracold ensembles of any negatively charged species. We have studied the aforementioned transition in a beam of negative La ions by high-resolution laser spectroscopy. The center-of-gravity frequency was measured to be 96.592 80(10) THz. Seven of the nine expected hyperfine structure transitions were resolved. The observed peaks were unambiguously assigned to the predicted hyperfine transitions by a fit, confirmed by multiconfigurational self-consistent field calculations. From the determined hyperfine structure we conclude that La^{-} is a promising laser cooling candidate. Using this transition, only three laser beams would be required to repump all hyperfine levels of the ground state.

  16. Chimiométrie appliquée à la spectroscopie de plasma induit par laser (LIBS) et à la spectroscopie terahertz

    OpenAIRE

    El Haddad, Josette

    2013-01-01

    The aim of this work was the application of multivariate methods to analyze spectral data from laser-induced breakdown spectroscopy (LIBS) and terahertz (THz) spectroscopy to improve the analytical ability of these techniques.In this work, the LIBS data were derived from on-site measurements of soil samples. The common univariate approach was not efficient enough for accurate quantitative analysis and consequently artificial neural networks (ANN) were applied. This allowed quantifying several...

  17. Detection of calculus by laser-induced breakdown spectroscopy (LIBS) using an ultra-short pulse laser system (USPL)

    Science.gov (United States)

    Schelle, F.; Brede, O.; Krueger, S.; Oehme, B.; Dehn, C.; Frentzen, M.; Braun, A.

    2011-03-01

    The aim of this study was to assess the detection of calculus by Laser Induced Breakdown Spectroscopy (LIBS). The study was performed with an Nd:YVO4 laser, emitting pulses with a duration of 8 ps at a wavelength of 1064 nm. A repetition rate of 500 kHz at an average power of 5 W was used. Employing a focusing lense, intensities of the order of 1011 W/cm2 were reached on the tooth surface. These high intensities led to the generation of a plasma. The light emitted by the plasma was collimated into a fibre and then analyzed by an echelle spectroscope in the wavelength region from 220 nm - 900 nm. A total number of 15 freshly extracted teeth was used for this study. For each tooth the spectra of calculus and cementum were assessed separately. Comprising all single measurements median values were calculated for the whole spectrum, leading to two specific spectra, one for calculus and one for cementum. For further statistical analysis 28 areas of interest were defined as wavelength regions, in which the signal strength differed regarding the material. In 7 areas the intensity of the calculus spectrum differed statistically significant from the intensity of the cementum spectrum (p minimally invasive method allowing a safe application in laser-guided dentistry.

  18. Emission enhancement of laser-induced breakdown spectroscopy by localized surface plasmon resonance for analyzing plant nutrients.

    Science.gov (United States)

    Ohta, Takayuki; Ito, Masafumi; Kotani, Takashi; Hattori, Takeaki

    2009-05-01

    We demonstrate the monitoring of plant nutrients in leaves of Citrus unshiu and Rhododendron obtusum using low-energy (laser-induced breakdown spectroscopy. The raw plant leaf was successfully ablated without desiccation before laser irradiation, by applying metallic colloidal particles to the leaf surface. The emission intensity with the metallic particles was larger than that without the particles. This result indicates an improvement of the sensitivity and the detection limit of laser-induced breakdown spectroscopy. The emission enhancement was caused by localized surface plasmon resonance and was dependent on the size and material of metallic particles.

  19. A conceptual design of the set-up for solid state spectroscopy with free electron laser and insertion device radiation

    CERN Document Server

    Makhov, V N

    2001-01-01

    The set-up for complex solid state spectroscopy with the use of enhanced properties of radiation from insertion devices and free electron lasers is proposed. Very high flux and pulsed properties of radiation from insertion devices and free electron lasers offer the possibility for the use of such powerful techniques as electron paramagnetic resonance (EPR) and optically detected magnetic resonance (ODMR) for the studies of excited states of electronic excitations or defects in solids. The power density of radiation can become high enough for one more method of exited-state spectroscopy: transient optical absorption spectroscopy. The set-up is supposed to combine the EPR/ODMR spectrometer, i.e. cryostat supplied with superconducting magnet and microwave system, and the optical channels for excitation (by radiation from insertion devices or free electron laser) and detection of luminescence (i.e. primary and secondary monochromators). The set-up can be used both for 'conventional' spectroscopy of solids (reflec...

  20. [Determination of minor elements in stainless steel by laser-induced plasma spectroscopy (LIPS)].

    Science.gov (United States)

    Li, Jing; Zhai, Chao; Zhang, Shi-Ding; Zhang, Jian-Qiu; Meng, Xiang-Ru

    2008-04-01

    Laser-induced plasma spectroscopy (LIPS) is characterized by its non-contact and real-time analysis. Its application to the determination of steel composition can meet the need of high-speed, continuous and automatic production in large steel companies. In the present article the minor elements concentrations of aluminum, manganese, cobalt, molybdenum, and titanium in a series of stainless steel 1Cr18Ni9Ti samples were determinate by laser-induced plasma spectroscopy, based on a Nd : YAG Q-switched solid laser with wavelength 1 064 nm as an exciting source and ICCD as detector. In the experiment the working delay time and gate time of ICCD were set suitably to get high signal-to-noise ratio emission spectral lines, and the internal standardization method related to matrix effect was used to deal with spectral data. Experiment results show that the concentration ratios of all the measured elements versus the reference element ferrum have a good linear relationship with the intensity ratios of them, the detection limits of the five tested elements are within 150 microg x g(-1).