WorldWideScience

Sample records for beam emission spectroscopy

  1. BATMAN beam properties characterization by the beam emission spectroscopy diagnostic

    Science.gov (United States)

    Bonomo, F.; Ruf, B.; Barbisan, M.; Cristofaro, S.; Schiesko, L.; Fantz, U.; Franzen, P.; Pasqualotto, R.; Riedl, R.; Serianni, G.; Wünderlich, D.

    2015-04-01

    The ITER neutral beam heating systems are based on the production and acceleration of negative ions (H/D) up to 1 MV. The requirements for the beam properties are strict: a low core beam divergence (BATMAN (BAvarian Test MAchine for Negative ions) allows for deepening the knowledge of the determination of the beam properties. One of the diagnostics routinely used to this purpose is the Beam Emission Spectroscopy (BES): the Hα light emitted in the beam is detected and the corresponding spectra are evaluated to estimate the beam divergence and the stripping losses. The BES number of lines of sight in BATMAN has been recently increased: five horizontal lines of sight providing a vertical profile of the beam permit to characterize the negative ion beam properties in relation to the source parameters. Different methods of Hα spectra analysis are here taken into account and compared for the estimation of the beam divergence and the amount of stripping. In particular, to thoroughly study the effect of the space charge compensation on the beam divergence, an additional hydrogen injection line has been added in the tank, which allows for setting different background pressure values (one order of magnitude, from about 0.04 Pa up to the source pressure) in the beam drift region.

  2. BATMAN beam properties characterization by the beam emission spectroscopy diagnostic

    Energy Technology Data Exchange (ETDEWEB)

    Bonomo, F., E-mail: federica.bonomo@igi.cnr.it [Consorzio RFX (CNR, ENEA, INFN, Università di Padova, Acciaierie Venete SpA), Corso Stati Uniti 4, 35127 Padova (Italy); Istituto Gas Ionizzati - CNR, Corso Stati Uniti 4, 35127 Padova (Italy); Ruf, B.; Schiesko, L.; Fantz, U.; Franzen, P.; Riedl, R.; Wünderlich, D. [Max-Planck-Institut für Plasmaphysik, Boltzmannstr. 2, 85748 Garching (Germany); Barbisan, M.; Pasqualotto, R.; Serianni, G. [Consorzio RFX (CNR, ENEA, INFN, Università di Padova, Acciaierie Venete SpA), Corso Stati Uniti 4, 35127 Padova (Italy); Cristofaro, S. [Universitá degli Studi di Padova, Via 8 Febbraio 2, 35122 Padova (Italy)

    2015-04-08

    The ITER neutral beam heating systems are based on the production and acceleration of negative ions (H/D) up to 1 MV. The requirements for the beam properties are strict: a low core beam divergence (< 0.4 °) together with a low source pressure (≤ 0.3 Pa) would permit to reduce the ion losses along the beamline, keeping the stripping particle losses below 30%. However, the attainment of such beam properties is not straightforward. At IPP, the negative ion source testbed BATMAN (BAvarian Test MAchine for Negative ions) allows for deepening the knowledge of the determination of the beam properties. One of the diagnostics routinely used to this purpose is the Beam Emission Spectroscopy (BES): the H{sub α} light emitted in the beam is detected and the corresponding spectra are evaluated to estimate the beam divergence and the stripping losses. The BES number of lines of sight in BATMAN has been recently increased: five horizontal lines of sight providing a vertical profile of the beam permit to characterize the negative ion beam properties in relation to the source parameters. Different methods of H{sub α} spectra analysis are here taken into account and compared for the estimation of the beam divergence and the amount of stripping. In particular, to thoroughly study the effect of the space charge compensation on the beam divergence, an additional hydrogen injection line has been added in the tank, which allows for setting different background pressure values (one order of magnitude, from about 0.04 Pa up to the source pressure) in the beam drift region.

  3. Combined hydrogen and lithium beam emission spectroscopy observation system for Korea Superconducting Tokamak Advanced Research

    Energy Technology Data Exchange (ETDEWEB)

    Lampert, M. [Wigner RCP, Euratom Association-HAS, Budapest (Hungary); BME NTI, Budapest (Hungary); Anda, G.; Réfy, D.; Zoletnik, S. [Wigner RCP, Euratom Association-HAS, Budapest (Hungary); Czopf, A.; Erdei, G. [Department of Atomic Physics, BME IOP, Budapest (Hungary); Guszejnov, D.; Kovácsik, Á.; Pokol, G. I. [BME NTI, Budapest (Hungary); Nam, Y. U. [National Fusion Research Institute, Daejeon (Korea, Republic of)

    2015-07-15

    A novel beam emission spectroscopy observation system was designed, built, and installed onto the Korea Superconducting Tokamak Advanced Research tokamak. The system is designed in a way to be capable of measuring beam emission either from a heating deuterium or from a diagnostic lithium beam. The two beams have somewhat complementary capabilities: edge density profile and turbulence measurement with the lithium beam and two dimensional turbulence measurement with the heating beam. Two detectors can be used in parallel: a CMOS camera provides overview of the scene and lithium beam light intensity distribution at maximum few hundred Hz frame rate, while a 4 × 16 pixel avalanche photo-diode (APD) camera gives 500 kHz bandwidth data from a 4 cm × 16 cm region. The optics use direct imaging through lenses and mirrors from the observation window to the detectors, thus avoid the use of costly and inflexible fiber guides. Remotely controlled mechanisms allow adjustment of the APD camera’s measurement location on a shot-to-shot basis, while temperature stabilized filter holders provide selection of either the Doppler shifted deuterium alpha or lithium resonance line. The capabilities of the system are illustrated by measurements of basic plasma turbulence properties.

  4. Comparison endpoint study of process plasma and secondary electron beam exciter optical emission spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Stephan Thamban, P. L.; Yun, Stuart; Padron-Wells, Gabriel; Hosch, Jimmy W.; Goeckner, Matthew J. [Department of Mechanical Engineering, University of Texas at Dallas, 800W Campbell Road, Richardson, Texas 75080 (United States); Department of Electrical Engineering, University of Texas at Dallas, 800W Campbell Road, Richardson, Texas 75080 (United States); Verity Instruments, Inc., 2901 Eisenhower Street, Carrollton, Texas 75007 (United States); Department of Mathematical Sciences, University of Texas at Dallas, 800 W Campbell Road, Richardson, Texas 75080 (United States)

    2012-11-15

    Traditionally process plasmas are often studied and monitored by optical emission spectroscopy. Here, the authors compare experimental measurements from a secondary electron beam excitation and direct process plasma excitation to discuss and illustrate its distinctiveness in the study of process plasmas. They present results that show excitations of etch process effluents in a SF{sub 6} discharge and endpoint detection capabilities in dark plasma process conditions. In SF{sub 6} discharges, a band around 300 nm, not visible in process emission, is observed and it can serve as a good indicator of etch product emission during polysilicon etches. Based on prior work reported in literature the authors believe this band is due to SiF{sub 4} gas phase species.

  5. Synthetic diagnostic for the beam emission spectroscopy diagnostic using a full optical integration

    Science.gov (United States)

    Hausammann, L.; Churchill, R. M.; Shi, L.

    2017-02-01

    The beam emission spectroscopy (BES) diagnostic is used to measure fluctuations of electron density in the edge and core of fusion plasmas, and is a key in understanding turbulence in a plasma reactor. A synthetic BES diagnostic for the turbulence simulation code XGC1 has been developed using a realistic neutral beam model and an optical system easily adaptable to different kinds of tokamaks. The beam is modeled using multiple beam energy components, each one with a fraction of the total energy and their own mass and energy (mono-energetic components). The optical system consists of a lens focusing a bundle of optical fibers and resulting in a 2D measurement. The synthetic diagnostic gives similar correlation functions and behaviour of the turbulences than the usual methods that do not take into account the full 3D optical effects. The results, based on a simulation of XGC1, contain an analysis of the correlation (in space and time), a comparison of different approximations possible and their importance in accurately modeling the BES diagnostic.

  6. Development of beam emission spectroscopy for turbulence transport study in Heliotron J

    Science.gov (United States)

    Kobayashi, S.; Ohshima, S.; Matsuda, H.; Lu, X. X.; Kokubu, D.; Ida, K.; Kobayashi, T.; Yoshinuma, M.; Kado, S.; Oishi, T.; Nagasaki, K.; Okada, H.; Minami, T.; Yamamoto, S.; Nakamura, Y.; Ishizawa, A.; Kenmochi, N.; Otani, Y.; Konoshima, S.; Mizuuchi, T.

    2016-11-01

    This paper describes the development study of the beam emission spectroscopy (BES) for the turbulent transport study in Heliotron J. Modification of the sightlines (10 × 4 for edge and 10 × 2 for edge) enables us to obtain 2-dimensional BES imaging. The cooling effect on the reduction in the electrical noise of avalanche photodiode (APD) assembly has been investigated using a refrigerant cooling system. When the temperature of the APD element has set to be -20 °C, the electrical noise can be reduced more than 50%. The measurement error of the phase difference in the case of low signal level has been tested by two light-emitting diode lamps. The APD cooling has an effect to improve the measurement error at the low signal level of APD.

  7. Active Beam Spectroscopy

    Science.gov (United States)

    von Hellermann, M. G.; Delabie, E.; Jaspers, R. J. E.; Biel, W.; Marchuk, O.; Summers, H. P.; Whiteford, A.; Giroud, C.; Hawkes, N. C.; Zastrow, K. D.

    2008-03-01

    Charge eXchange Recombination Spectroscopy (CXRS) plays a pivotal role in the diagnostics of hot fusion plasmas and is implemented currently in most of the operating devices. In the present report the main features of CXRS are summarized and supporting software packages encompassing "Spectral Analysis Code CXSFIT", "Charge Exchange Analysis Package CHEAP", and finally "Forward Prediction of Spectral Features" are described. Beam Emission Spectroscopy (BES) is proposed as indispensable cross-calibration tool for absolute local impurity density measurements and also for the continuous monitoring of the neutral beam power deposition profile. Finally, a full exploitation of the `Motional Stark Effect' pattern is proposed to deduce local pitch angles, total magnetic fields and possibly radial electric fields. For the proposed active beam spectroscopy diagnostic on ITER comprehensive performance studies have been carried out. Estimates of expected spectral signal-to-noise ratios are based on atomic modelling of neutral beam stopping and emissivities for CXRS, BES and background continuum radiation as well as extrapolations from present CXRS diagnostic systems on JET, Tore Supra, TEXTOR and ASDEX-UG. Supplementary to thermal features a further promising application of CXRS has been proposed recently for ITER, that is a study of slowing-down alpha particles in the energy range up to 2 MeV making use of the 100 keV/amu DNB (Diagnostic Neutral Beam) and the 500 keV/amu HNB (Heating Neutral Beam). Synthetic Fast Ion Slowing-Down spectra are evaluated in terms of source rates and slowing-down parameters

  8. A synthetic diagnostic for beam emission spectroscopy in the helically symmetric experiment stellarator

    Science.gov (United States)

    Dobbins, T. J.; Kumar, S. T. A.; Anderson, D. T.

    2016-11-01

    The Helically Symmetric Experiment (HSX) has a number of active spectroscopy diagnostics. Due to the relatively large beam width compared to the plasma minor radius, it is difficult to achieve good spatial resolution at the core of the HSX plasma. This is due to the fact that the optical sightline cuts through many flux surfaces with varying field vectors within the beam. In order to compare the experimental results with theoretical models it is important to accurately model the beam width effects. A synthetic diagnostic has been developed for this purpose. This synthetic diagnostic calculates the effect of spot size and beam width on the measurements of quantities of interest, including radial electric field, flow velocity, and Stark polarization.

  9. Method to obtain absolute impurity density profiles combining charge exchange and beam emission spectroscopy without absolute intensity calibrationa)

    Science.gov (United States)

    Kappatou, A.; Jaspers, R. J. E.; Delabie, E.; Marchuk, O.; Biel, W.; Jakobs, M. A.

    2012-10-01

    Investigation of impurity transport properties in tokamak plasmas is essential and a diagnostic that can provide information on the impurity content is required. Combining charge exchange recombination spectroscopy (CXRS) and beam emission spectroscopy (BES), absolute radial profiles of impurity densities can be obtained from the CXRS and BES intensities, electron density and CXRS and BES emission rates, without requiring any absolute calibration of the spectra. The technique is demonstrated here with absolute impurity density radial profiles obtained in TEXTOR plasmas, using a high efficiency charge exchange spectrometer with high etendue, that measures the CXRS and BES spectra along the same lines-of-sight, offering an additional advantage for the determination of absolute impurity densities.

  10. Method to obtain absolute impurity density profiles combining charge exchange and beam emission spectroscopy without absolute intensity calibration

    Energy Technology Data Exchange (ETDEWEB)

    Kappatou, A.; Delabie, E. [FOM Institute DIFFER - Dutch Institute for Fundamental Energy Research, Association EURATOM-FOM, 3430 BE Nieuwegein (Netherlands); Jaspers, R. J. E.; Jakobs, M. A. [Science and Technology of Nuclear Fusion, Eindhoven University of Technology, 5600 MB Eindhoven (Netherlands); Marchuk, O.; Biel, W. [Institute for Energy and Climate Research, Forschungszentrum Julich GmbH, Trilateral Euregio Cluster, 52425 Julich (Germany)

    2012-10-15

    Investigation of impurity transport properties in tokamak plasmas is essential and a diagnostic that can provide information on the impurity content is required. Combining charge exchange recombination spectroscopy (CXRS) and beam emission spectroscopy (BES), absolute radial profiles of impurity densities can be obtained from the CXRS and BES intensities, electron density and CXRS and BES emission rates, without requiring any absolute calibration of the spectra. The technique is demonstrated here with absolute impurity density radial profiles obtained in TEXTOR plasmas, using a high efficiency charge exchange spectrometer with high etendue, that measures the CXRS and BES spectra along the same lines-of-sight, offering an additional advantage for the determination of absolute impurity densities.

  11. Measuring one-dimensional and two-dimensional impurity density profiles on TEXTOR using combined charge exchange-beam emission spectroscopy and ultrasoft x-ray tomography

    Science.gov (United States)

    De Bock, M.; Jakubowska, K.; Hellermann, M. von; Jaspers, R.; Donné, A. J. H.; Shmaenok, L.

    2004-10-01

    Two techniques are presented that allow us to measure impurity density profiles in the TEXTOR tokamak plasma. The one-dimensional profiles are gathered by charge exchange recombination spectroscopy (CXRS) in combination with beam emission spectroscopy (BES). Combining CXRS and BES eliminate the need for absolute calibration. For two-dimensional profiles an ultrasoft x-ray tomography system has been developed. The system is spectrally resolved and produces local emissivity profiles of several ionization stages of impurities. Both systems are presently being commissioned. They are complementary and give an insight into the impurity distribution and transport in plasmas.

  12. Photoelectron photoion molecular beam spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Trevor, D.J.

    1980-12-01

    The use of supersonic molecular beams in photoionization mass spectroscopy and photoelectron spectroscopy to assist in the understanding of photoexcitation in the vacuum ultraviolet is described. Rotational relaxation and condensation due to supersonic expansion were shown to offer new possibilities for molecular photoionization studies. Molecular beam photoionization mass spectroscopy has been extended above 21 eV photon energy by the use of Stanford Synchrotron Radiation Laboratory (SSRL) facilities. Design considerations are discussed that have advanced the state-of-the-art in high resolution vuv photoelectron spectroscopy. To extend gas-phase studies to 160 eV photon energy, a windowless vuv-xuv beam line design is proposed.

  13. Active beam spectroscopy for ITER

    Energy Technology Data Exchange (ETDEWEB)

    Von Hellermann, M.; Giroud, C.; Jaspers, R. [Association Euratom-Fom, FOM Institute for Plasma Physics Rijnhuizen, Trilateral Euregio Cluster (Netherlands); Hawkes, N.C.; Mullane, M.O.; Zastrow, K.D. [Euratom/UKAEA Fusion Association, Culham Science Centre, Abingdon (United Kingdom); Krasilnikov, A.; Tugarinov, S. [SRC RF TRINITI, Troitsk, Moscow region (Russian Federation); Lotte, P. [Association Euratom-CEA Cadarache, 13 - Saint-Paul-lez-Durance (France). Dept. de Recherches sur la Fusion Controlee; McKee, G. [Wisconsin Univ., Madison, WI (United States); Malaquias, A. [Associacao EURATOM/IST, Instituto Superior Tecnico, Lisboa (Portugal); Rachlew, E. [Kungliga Tekniska Hoegskolan (KTH), Stockholm(Sweden)

    2003-07-01

    The latest status of 'Active Beam' related spectroscopy aspects as part of the ITER diagnostic scenario is presented. A key issue of the proposed scheme is based on the concept that in order to achieve the ultimate goal of global data consistency, all particles involved, that is, intrinsic and seeded impurity ions as well as helium ash ions and bulk plasma ions and also the plasma background data (e.g. magnetic and electric fields, electron density and temperature profiles) need to be addressed. A further sensible step in this direction is the decision of exploiting both a dedicated low-energy, low-power diagnostic beam (DNB, 2.2 MW 100 keV/amu) as well as the high-power, high-energy heating beams (HNB, 17 MW 500 keV/amu) for maximum diagnostic information. The authors report some new aspects referring to the use of DNB for motional Stark effect (MSE) where the main idea is to treat both beams (HNB and DNB) as potential diagnostic tools with complementary roles. The equatorial ports for the DNB promise excellent spatial resolution, however, the angles are less favourable for a polarimetric MSE exploitation. HNB can be used as probe beam for diagnosing slowing-down fusion alpha with a birth energy of 3,5 MeV.

  14. Active beam spectroscopy for ITER

    Energy Technology Data Exchange (ETDEWEB)

    Hellermann, M.G. von, E-mail: mgvh@jet.u [FOM Institute Rijnhuizen, Euratom Association, 3430BE Nieuwegein (Netherlands); Barnsley, R. [ITER Organization, 13108 St.-Paul-Lez-Durance, Cadarache (France); Biel, W. [Institut fuer Energieforschung, Plasmaphysik, Forschungszentrum Juelich, Euratom Association, 52425 Juelich (Germany); Delabie, E. [FOM Institute Rijnhuizen, Euratom Association, 3430BE Nieuwegein (Netherlands); Hawkes, N. [Culham Centre for Fusion Energy, Euratom Association, Culham OX14 3DB (United Kingdom); Jaspers, R. [FOM Institute Rijnhuizen, Euratom Association, 3430BE Nieuwegein (Netherlands); Johnson, D. [Princeton Plasma Physics Laboratory, Princeton, NJ-08548 (United States); Klinkhamer, F. [TNO Science and Industry, Stieltjesweg 1, 2628CK Delft (Netherlands); Lischtschenko, O. [FOM Institute Rijnhuizen, Euratom Association, 3430BE Nieuwegein (Netherlands); Marchuk, O. [Institut fuer Energieforschung, Plasmaphysik, Forschungszentrum Juelich, Euratom Association, 52425 Juelich (Germany); Schunke, B. [ITER Organization, 13108 St.-Paul-Lez-Durance, Cadarache (France); Singh, M.J. [Institute for Plasma Research, Bhat, Gandhinagar, Gurajat 384828 (India); Snijders, B. [TNO Science and Industry, Stieltjesweg 1, 2628CK Delft (Netherlands); Summers, H.P. [Culham Centre for Fusion Energy, Euratom Association, Culham OX14 3DB (United Kingdom); Thomas, D. [ITER Organization, 13108 St.-Paul-Lez-Durance, Cadarache (France); Tugarinov, S. [TRINITI Troitsk, Moscow Region 142092 (Russian Federation); Vasu, P. [Institute for Plasma Research, Bhat, Gandhinagar, Gurajat 384828 (India)

    2010-11-11

    Since the first feasibility studies of active beam spectroscopy on ITER in 1995 the proposed diagnostic has developed into a well advanced and mature system. Substantial progress has been achieved on the physics side including comprehensive performance studies based on an advanced predictive code, which simulates active and passive features of the expected spectral ranges. The simulation has enabled detailed specifications for an optimized instrumentation and has helped to specify suitable diagnostic neutral beam parameters. Four ITER partners share presently the task of developing a suite of ITER active beam diagnostics, which make use of the two 0.5 MeV/amu 18 MW heating neutral beams and a dedicated 0.1 MeV/amu, 3.6 MW diagnostic neutral beam. The IN ITER team is responsible for the DNB development and also for beam physics related aspects of the diagnostic. The RF will be responsible for edge CXRS system covering the outer region of the plasma (1>r/a>0.4) using an equatorial observation port, and the EU will develop the core CXRS system for the very core (0

  15. Chiral specific electron vortex beam spectroscopy

    CERN Document Server

    Yuan, J; Babiker, M

    2013-01-01

    Electron vortex beams carry well-defined orbital angular momentum (OAM) about the propagation axis. Such beams are thus characterised by chirality features which make them potentially useful as probes of magnetic and other chiral materials. An analysis of the inelastic processes in which electron vortex beams interact with atoms and which involve OAM exchange is outlined, leading to the multipolar selection rules governing this chiral specific electron vortex beam spectroscopy. Our results show clearly that the selection rules are dependent on the dynamical state and location of the atoms involved. In the most favorable scenario, this form of electron spectroscopy can induce magnetic sublevel transitions which are commonly probed using circularly polarized photon beams.

  16. Relativistic atomic beam spectroscopy II

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1991-12-31

    We are requesting support for a postdoctoral person to participate in H{sup -} studies at Los Alamos. In addition, we are requesting funding for a state-of-the-art YAG laser system that would allow us to obtain data at three times our present rate with improved beam quality.

  17. Mid infrared emission spectroscopy of carbon plasma

    Science.gov (United States)

    Nemes, Laszlo; Brown, Ei Ei; Yang, Clayton S.-C.; Hommerich, Uwe

    2017-01-01

    Mid infrared time-resolved emission spectra were recorded from laser-induced carbon plasma. These spectra constitute the first study of carbon materials LIB spectroscopy in the mid infrared range. The carbon plasma was induced using a Q-switched Nd: YAG laser. The laser beam was focused to high purity graphite pellets mounted on a translation stage. Mid infrared emission from the plasma in an atmospheric pressure background gas was detected by a cooled HgCdTe detector in the range 4.4-11.6 μm, using long-pass filters. LIB spectra were taken in argon, helium and also in air. Despite a gate delay of 10 μs was used there were strong backgrounds in the spectra. Superimposed on this background broad and noisy emission bands were observed, the form and position of which depended somewhat on the ambient gas. The spectra were digitally smoothed and background corrected. In argon, for instance, strong bands were observed around 4.8, 6.0 and 7.5 μm. Using atomic spectral data by NIST it could be concluded that carbon, argon, helium and nitrogen lines from neutral and ionized atoms are very weak in this spectral region. The width of the infrared bands supports molecular origin. The infrared emission bands were thus compared to vibrational features of carbon molecules (excluding C2) of various sizes on the basis of previous carbon cluster infrared absorption and emission spectroscopic analyses in the literature and quantum chemical calculations. Some general considerations are given about the present results.

  18. Mid infrared emission spectroscopy of carbon plasma.

    Science.gov (United States)

    Nemes, Laszlo; Brown, Ei Ei; S-C Yang, Clayton; Hommerich, Uwe

    2017-01-05

    Mid infrared time-resolved emission spectra were recorded from laser-induced carbon plasma. These spectra constitute the first study of carbon materials LIB spectroscopy in the mid infrared range. The carbon plasma was induced using a Q-switched Nd: YAG laser. The laser beam was focused to high purity graphite pellets mounted on a translation stage. Mid infrared emission from the plasma in an atmospheric pressure background gas was detected by a cooled HgCdTe detector in the range 4.4-11.6μm, using long-pass filters. LIB spectra were taken in argon, helium and also in air. Despite a gate delay of 10μs was used there were strong backgrounds in the spectra. Superimposed on this background broad and noisy emission bands were observed, the form and position of which depended somewhat on the ambient gas. The spectra were digitally smoothed and background corrected. In argon, for instance, strong bands were observed around 4.8, 6.0 and 7.5μm. Using atomic spectral data by NIST it could be concluded that carbon, argon, helium and nitrogen lines from neutral and ionized atoms are very weak in this spectral region. The width of the infrared bands supports molecular origin. The infrared emission bands were thus compared to vibrational features of carbon molecules (excluding C2) of various sizes on the basis of previous carbon cluster infrared absorption and emission spectroscopic analyses in the literature and quantum chemical calculations. Some general considerations are given about the present results.

  19. Modelling and Evaluation of Spectra in Beam Aided Spectroscopy

    Science.gov (United States)

    von Hellermann, M. G.; Delabie, E.; Jaspers, R.; Lotte, P.; Summers, H. P.

    2008-10-01

    The evaluation of active beam induced spectra requires advanced modelling of both active and passive features. Three types of line shapes are addressed in this paper: Thermal spectra representing Maxwellian distribution functions described by Gaussian-like line shapes, secondly broad-band fast ion spectra with energies well above local ion temperatures, and, finally, the narrow lines shapes of the equi-spaced Motion Stark multiplet (MSE) of excited neutral beam particles travelling through the magnetic field confining the plasma. In each case additional line shape broadening caused by Gaussian-like instrument functions is taken into account. Further broadening effects are induced by collision velocity dependent effective atomic rates where the observed spectral shape is the result of a convolution of emission rate function and velocity distribution function projected into the direction of observation. In the case of Beam Emission Spectroscopy which encompasses the Motional Stark features, line broadening is also caused by the finite angular spread of injected neutrals and secondly by a ripple in the acceleration voltage associated with high energy neutral beams.

  20. Electron-beam-sustained discharge revisited - light emission from combined electron beam and microwave excited argon at atmospheric pressure

    CERN Document Server

    Dandl, T; Neumeier, A; Wieser, J; Ulrich, A

    2015-01-01

    A novel kind of electron beam sustained discharge is presented in which a 12keV electron beam is combined with a 2.45GHz microwave power to excite argon gas at atmospheric pressure in a continuous mode of operation. Optical emission spectroscopy is performed over a wide wavelength range from the vacuum ultraviolet (VUV) to the near infrared (NIR). Several effects which modify the emission spectra compared to sole electron beam excitation are observed and interpreted by the changing plasma parameters such as electron density, electron temperature and gas temperature.

  1. Spectroscopy with Hadrons Beams at COMPASS

    CERN Document Server

    CERN. Geneva

    2007-01-01

    Following numerous interactions with the SPSC in 2007 we review projected capa- bilities of the COMPASS spectrometer in the field of light hadron spectroscopy. The paper describes in detail a full simulation with subsequent partial wave analysis of two final states for central production. Both, neutral and all charged states can very well be observed and analyzed within COMPASS. In addition we show the result of a full partial wave analysis of data taken in the pilot run 2004 using the diffractively produced $\\pi^+\\pi^-\\pi^-$ final state. The results agree remarkably well with previous data taken an BNL. We also vaticinate the physics data sample expected for 2008, using projected beam times for different reaction mechanisms.

  2. Applications and advances of positron beam spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Howell, R., LLNL

    1998-03-18

    Over 50 scientists from DOE-DP, DOE-ER, the national laboratories, academia and industry attended a workshop held on November 5-7, 1997 at Lawrence Livermore National Laboratory. Workshop participants were charged to address two questions: Is there a need for a national center for materials analysis using positron techniques and can the capabilities at Lawrence Livermore National Laboratory serve this need. To demonstrate the need for a national center, the workshop participants discussed the technical advantages enabled by high positron currents and advanced measurement techniques, the role that these techniques would play in materials analysis and the demand for the data. Livermore now leads the world in materials analysis capabilities by positrons due to developments in response to demands of stockpile stewardship. The Livermore facilities now include the world`s highest current beam of keV positrons, a scanning pulsed positron microprobe under development capable of three dimensional maps of defect size and concentration, an MeV positron beam for defect analysis of large samples, and electron momentum spectroscopy by positrons. It was concluded that the positron microprobe under development at LLNL and other new instruments that would be relocated at LLNL at the high current keV source are an exciting step forward in providing results for the positron technique. These new data will impact a wide variety of applications.

  3. Optimized frequency dependent photothermal beam deflection spectroscopy

    Science.gov (United States)

    Korte, D.; Cabrera, H.; Toro, J.; Grima, P.; Leal, C.; Villabona, A.; Franko, M.

    2016-12-01

    In the letter the optimization of the experimental setup for photothermal beam deflection spectroscopy is performed by analyzing the influence of its geometrical parameters (detector and sample position, probe beam radius and its waist position etc) on the detected signal. Furthermore, the effects of the fluid’s thermo-optical properties, for optimized geometrical configuration, on the measurement sensitivity and uncertainty determination of sample thermal properties is also studied. The examined sample is a recently developed CuFeInTe3 material. It is seen from the obtained results, that it is a complex problem to choose the proper geometrical configuration as well as sensing fluid to enhance the sensitivity of the method. A signal enhancement is observed at low modulation frequencies by placing the sample in acetonitrile (ACN), while at high modulation frequencies the sensitivity is higher for measurements made in air. For both, detection in air and acetonitrile the determination of CuFeInTe3 thermal properties is performed. The determined values of thermal diffusivity and thermal conductivity are (0.048  ±  0.002)  ×  10-4 m2 s-1 and 4.6  ±  0.2 W m-1 K-1 and (0.056  ±  0.005)  ×  10-4 m2 s-1 and 4.8  ±  0.4 W m-1 K-1 for ACN and air, respectively. It is seen, that the determined values agree well within the range of their measurement uncertainties for both cases, although the measurement uncertainty is two times lower for the measurements in ACN providing more accurate results. The analysis is performed by the use of recently developed theoretical description based on the complex geometrical optics. It is also shown, how the presented work fits into the current status of photothermal beam deflection spectroscopy.

  4. Photon emission spectroscopy of ion-atom collisions

    Energy Technology Data Exchange (ETDEWEB)

    Nystroem, B.

    1995-10-01

    Emission cross sections for the 1snp{sup 1}P{sub 1}-levels have been measured by photon emission spectroscopy for the collision systems He{sup +} + He at 10 keV and He{sup 2+} + He at 10-35 keV. Photon spectra of Krypton (Kr VIII) and Xenon (Xe V - IX) have also been obtained using 10q keV beams of Kr{sup q+} (q=7-9) and Xe{sup q+} (q=5-9) colliding with Helium and Argon. The Lifetimes of 3p{sup 2}P-levels in Na-like Nb are reported together with lifetime for the 3s3p{sup 3}P{sub 1}-level in Mg-like Ni, Kr, Y, Zr and Nb where this level has an intercombination transition to the ground state. 45 refs, 20 figs.

  5. In-beam spectroscopy of the heaviest elements

    Science.gov (United States)

    Herzberg, Rolf-Dietmar

    2016-12-01

    In-beam spectroscopy provides many powerful tools for the detailed study of nuclear structure. Over the past two decades the coupling of sensitive in-beam spectrometers to recoil separators has allowed the study of weakly populated reaction channels, such as the fusion-evaporation reactions leading to nuclei beyond fermium (Z = 100). The methods, observables, and limitations of this approach are discussed.

  6. Applications of beam-foil spectroscopy to atomic collisions in solids

    Science.gov (United States)

    Sellin, I. A.

    1976-01-01

    Some selected papers presented at the Fourth International Conference on Beam-Foil Spectroscopy, whose results are of particular pertinence to ionic collision phenomena in solids, are reviewed. The topics discussed include solid target effects and means of surmounting them in the measurement of excited projectile ion lifetimes for low-energy heavy element ions; the electron emission accompanying the passage of heavy particles through solid targets; the collision broadening of X rays emitted from 100 keV ions moving in solids; residual K-shell excitation in chlorine ions penetrating carbon; comparison between 40 MeV Si on gaseous SiH4 targets at 300 mtorr and 40 MeV Si on Al; and the emergent surface interaction in beam-foil spectroscopy. A distinct overlap of interests between the sciences of beam-foil spectroscopy and atomic collisions in solids is pointed out.

  7. THz Emission Spectroscopy for THz Spintronics

    Science.gov (United States)

    Jarik Huisman, Thomas; Rasing, Theo

    2017-01-01

    Spintronics is used as the standard for the readout of magnetically stored data and also has commercial applications for writing data. The generation, control and detection of spin-polarized currents, spin-dependent electric transport, and pure spin currents on the subpicosecond (10-12 s) timescale are the next challenges in spintronics. Terahertz (THz, 1012 Hz) emission spectroscopy has proven to be an excellent tool for investigating these challenges. In this short review, we outline the functioning of this spectroscopic technique and its recent applications to spintronics.

  8. Consistency of atomic data for the interpretation of beam emission spectra

    Energy Technology Data Exchange (ETDEWEB)

    Delabie, E; Von Hellermann, M G [FOM Institute for Plasma Physics Rijnhuizen, Association EURATOM-FOM, PO Box 1207, 3430 BE Nieuwegein (Netherlands); Brix, M; Giroud, C; Surrey, E; Zastrow, K D [EURATOM/CCFE Association, Culham Science Centre, Abingdon, OX14 3DB (United Kingdom); Jaspers, R J E [Eindhoven University of Technology, Postbus 513, 5600 MB Eindhoven (Netherlands); Marchuk, O [Forschungszentrum Juelich, Association EURATOM-FZJ, 52425, Juelich (Germany); O' Mullane, M G [Department of Physics, University of Strathclyde, 107 Rottenrow, Glasgow G4 0NG (United Kingdom); Ralchenko, Yu, E-mail: e.delabie@fz-juelich.d [Atomic Physics Division, National Institute of Standards and Technology, Gaithersburg, MD 20899-8422 (United States)

    2010-12-15

    Several collisional-radiative (CR) models (Anderson et al 2000 Plasma Phys. Control. Fusion 42 781-806, Hutchinson 2002 Plasma Phys. Control. Fusion 44 71-82, Marchuk et al 2008 Rev. Sci. Instrum. 79 10F532) have been developed to calculate the attenuation and the population of excited states of hydrogen or deuterium beams injected into tokamak plasmas. The datasets generated by these CR models are needed for the modelling of beam ion deposition and (excited) beam densities in current experiments, and the reliability of these data will be crucial to obtain helium ash densities on ITER combining charge exchange and beam emission spectroscopy. Good agreement between the different CR models for the neutral beam (NB) is found, if corrections to the fundamental cross sections are taken into account. First the H{sub {alpha}} and H{sub {beta}} beam emission spectra from JET are compared with the expected intensities. Second, the line ratios within the Stark multiplet are compared with the predictions of a sublevel resolved model. The measured intensity of the full multiplet is {approx}30% lower than expected on the basis of beam attenuation codes and the updated beam emission rates, but apart from the atomic data this could also be due to the characterization of the NB path and line of sight integration and the absolute calibration of the optics. The modelled n = 3 to n = 4 population agrees very well with the ratio of the measured H{sub {alpha}} to H{sub {beta}} beam emission intensities. Good agreement is found as well between the NB power fractions measured with beam emission in plasma and on the JET Neutral Beam Test Bed. The Stark line ratios and {sigma}/{pi} intensity ratio deviate from a statistical distribution, in agreement with the CR model in parabolic states from Marchuk et al (2010 J. Phys. B: At. Mol. Opt. Phys. 43 011002).

  9. Molecular-beam spectroscopy of interhalogen molecules

    Energy Technology Data Exchange (ETDEWEB)

    Sherrow, S.A.

    1983-08-01

    A molecular-beam electric-resonance spectrometer employing a supersonic nozzle source has been used to obtain hyperfine spectra of /sup 79/Br/sup 35/Cl. Analyses of these spectra and of microwave spectra published by other authors have yielded new values for the electric dipole moment and for the nuclear quadrupole coupling constants in this molecule. The new constants are significantly different from the currently accepted values. Van der Waals clusters containing chlorine monofluoride have been studied under various expansion conditions by the molecular-beam electric-deflection method. The structural possibilities indicated by the results are discussed, and cluster geometries are proposed.

  10. Polarization Studies in Fast-Ion Beam Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Trabert, E

    2001-12-20

    In a historical review, the observations and the insight gained from polarization studies of fast ions interacting with solid targets are presented. These began with J. Macek's recognition of zero-field quantum beats in beam-foil spectroscopy as indicating alignment, and D.G. Ellis' density operator analysis that suggested the observability of orientation when using tilted foils. Lastly H. Winter's studies of the ion-beam surface interaction at grazing incidence yielded the means to produce a high degree of nuclear orientation in ion beams.

  11. Regimes of enhanced electromagnetic emission in beam-plasma interactions

    Energy Technology Data Exchange (ETDEWEB)

    Timofeev, I. V.; Annenkov, V. V.; Arzhannikov, A. V. [Budker Institute of Nuclear Physics, SB RAS, 630090 Novosibirsk, Russia and Novosibirsk State University, 630090 Novosibirsk (Russian Federation)

    2015-11-15

    The ways to improve the efficiency of electromagnetic waves generation in laboratory experiments with high-current relativistic electron beams injected into a magnetized plasma are discussed. It is known that such a beam can lose, in a plasma, a significant part of its energy by exciting a high level of turbulence and heating plasma electrons. Beam-excited plasma oscillations may simultaneously participate in nonlinear processes resulting in a fundamental and second harmonic emissions. It is obvious, however, that in the developed plasma turbulence the role of these emissions in the total energy balance is always negligible. In this paper, we investigate whether electromagnetic radiation generated in the beam-plasma system can be sufficiently enhanced by the direct linear conversion of resonant beam-driven modes into electromagnetic ones on preformed regular inhomogeneities of plasma density. Due to the high power of relativistic electron beams, the mechanism discussed may become the basis for the generator of powerful sub-terahertz radiation.

  12. Regimes of enhanced electromagnetic emission in beam-plasma interactions

    Science.gov (United States)

    Timofeev, I. V.; Annenkov, V. V.; Arzhannikov, A. V.

    2015-11-01

    The ways to improve the efficiency of electromagnetic waves generation in laboratory experiments with high-current relativistic electron beams injected into a magnetized plasma are discussed. It is known that such a beam can lose, in a plasma, a significant part of its energy by exciting a high level of turbulence and heating plasma electrons. Beam-excited plasma oscillations may simultaneously participate in nonlinear processes resulting in a fundamental and second harmonic emissions. It is obvious, however, that in the developed plasma turbulence the role of these emissions in the total energy balance is always negligible. In this paper, we investigate whether electromagnetic radiation generated in the beam-plasma system can be sufficiently enhanced by the direct linear conversion of resonant beam-driven modes into electromagnetic ones on preformed regular inhomogeneities of plasma density. Due to the high power of relativistic electron beams, the mechanism discussed may become the basis for the generator of powerful sub-terahertz radiation.

  13. 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.

  14. Characterisation of neutral hydrogen beam by means of active balmer-a-spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Wachter, C

    1999-01-01

    Neutral particle beams are used in thermal nuclear experiments for plasma heating and current drive, and as a diagnostic tool for active spectroscopy. Within the frame of this thesis eight viewing lines for H{sub {alpha}}-spectroscopy have been installed at the end of the injector to observe the fully established neutral beam. The viewing lines are all parallel to the horizontal plane and include small angles with the beam axis, in order to make use of the Doppler effect which separates the signals from the three energy components from each other and from the H{sub {alpha}}-emission of the thermal particles. A multi-Gaussian fit code has been applied to give the amplitudes, positions and widths of the Gauss shaped signals. From this data, the beam composition and, including the physics processes in the acceleration and neutralisation sections, the ion species fractions in the source have been calculated. Furthermore, the vertical density profile and an estimation of the absolute particle density distribution based on an absolute calibration resulted. From the line positions the exact acceleration voltage has been obtained. The line widths allow an estimate of the horizontal divergence. During this work, two ion sources, the 'Pagoda' and the 'Sourcette', have been investigated to obtain the ion species ratio and beam profile. The comparison of the spectroscopic with the calorimetric results gives a useful insight into the beam steering geometry. (author)

  15. Impact of diagnostic neutral beam optimization on active spectroscopy in MST

    Science.gov (United States)

    Feng, Xiande; Nornberg, Mark. D.; den Hartog, Daniel. J.; Oliva, Steven. P.; Craig, Darren; Univ of Wisconsin, Madison Team; Wheaton College, IL Collaboration

    2016-10-01

    The hydrogen diagnostic neutral beam on MST provides local measurements of impurity ion emission through charge exchange recombination spectroscopy (CHERS) and of core-localized magnetic field through the motional Stark effect (MSE). The beam has been optimized to operate at 50kV, 4A steady beam current with 20ms beam pulse and 75% primary energy ion fraction. It's achieved by tuning the beam voltage, arc current, fuel line pressure, arc and high voltage module timing, and the magnetic isolation field. Electron density measurements in the ion source revealed that ion extraction is maximized under low density conditions which are thought to affect the shape of the ion sheath at the extraction grid. The sheath may be transitioning from a planar or convex shape at high density to one which is concave which helps focus the ion trajectories and produce higher beam current. With the improvements in beam operation, the CHERS signal is expected to increase by 20%-30%, and the Stark broadening is expected to increase by 10%. These signal increases will help resolve convolved fine-structure components in both analyses. Beam voltage ripple is also measured to better quantify the accuracy of spectral MSE and CHERS measurement. This work is supported by the U.S. DOE.

  16. PLASMA EMISSION BY COUNTER-STREAMING ELECTRON BEAMS

    Energy Technology Data Exchange (ETDEWEB)

    Ziebell, L. F.; Petruzzellis, L. T.; Gaelzer, R. [Instituto de Física, UFRGS, Porto Alegre, RS (Brazil); Yoon, P. H. [Institute for Physical Science and Technology, University of Maryland, College Park, MD (United States); Pavan, J., E-mail: luiz.ziebell@ufrgs.br, E-mail: yoonp@umd.edu, E-mail: joel.pavan@ufpel.edu.br [Instituto de Física e Matemática, UFPel, Pelotas, RS (Brazil)

    2016-02-10

    The radiation emission mechanism responsible for both type-II and type-III solar radio bursts is commonly accepted as plasma emission. Recently Ganse et al. suggested that type-II radio bursts may be enhanced when the electron foreshock geometry of a coronal mass ejection contains a double hump structure. They reasoned that the counter-streaming electron beams that exist between the double shocks may enhance the nonlinear coalescence interaction, thereby giving rise to more efficient generation of radiation. Ganse et al. employed a particle-in-cell simulation to study such a scenario. The present paper revisits the same problem with EM weak turbulence theory, and show that the fundamental (F) emission is not greatly affected by the presence of counter-streaming beams, but the harmonic (H) emission becomes somewhat more effective when the two beams are present. The present finding is thus complementary to the work by Ganse et al.

  17. Liquid-Arc/Spark-Excitation Atomic-Emission Spectroscopy

    Science.gov (United States)

    Schlagen, Kenneth J.

    1992-01-01

    Constituents of solutions identified in situ. Liquid-arc/spark-excitation atomic-emission spectroscopy (LAES) is experimental variant of atomic-emission spectroscopy in which electric arc or spark established in liquid and spectrum of light from arc or spark analyzed to identify chemical elements in liquid. Observations encourage development of LAES equipment for online monitoring of process streams in such industries as metal plating, electronics, and steel, and for online monitoring of streams affecting environment.

  18. 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).

  19. Determination of Serum Lithium by Flame Emission Spectroscopy

    Directory of Open Access Journals (Sweden)

    R. Nafissy

    1976-07-01

    Full Text Available Lithum can be de termined both by atomic absorption spectroscopy andflame emission spectroscopy. We have used the later method with a Zeiss Model pMQlI spectro photometer fitt ed with ante-chamber atomizer and a potensiome rric line recorder. Accurate ana lysis for the clement was acco mplished due to a sophisracared measuring instrument.

  20. Compact, accurate description of diagnostic neutral beam propagation and attenuation in a high temperature plasma for charge exchange recombination spectroscopy analysis.

    Science.gov (United States)

    Bespamyatnov, Igor O; Rowan, William L; Granetz, Robert S

    2008-10-01

    Charge exchange recombination spectroscopy on Alcator C-Mod relies on the use of the diagnostic neutral beam injector as a source of neutral particles which penetrate deep into the plasma. It employs the emission resulting from the interaction of the beam atoms with fully ionized impurity ions. To interpret the emission from a given point in the plasma as the density of emitting impurity ions, the density of beam atoms must be known. Here, an analysis of beam propagation is described which yields the beam density profile throughout the beam trajectory from the neutral beam injector to the core of the plasma. The analysis includes the effects of beam formation, attenuation in the neutral gas surrounding the plasma, and attenuation in the plasma. In the course of this work, a numerical simulation and an analytical approximation for beam divergence are developed. The description is made sufficiently compact to yield accurate results in a time consistent with between-shot analysis.

  1. Combined in-beam gamma-ray and conversion electron spectroscopy with radioactive ion beams

    Directory of Open Access Journals (Sweden)

    Konki J.

    2013-12-01

    Full Text Available In-beam gamma-ray and electron spectroscopy have been widely used as tools to study the broad variety of phenomena in nuclear structure. The SPEDE spectrometer is a new device to be used in conjunction with the MINIBALL germanium detector array to enable the detection of internal conversion electrons in coincidence with gamma rays from de-exciting nuclei in radioactive ion beam experiments at the upcoming HIE-ISOLDE facility at CERN, Switzerland. Geant4 simulations were carried out in order to optimise the design and segmentation of the silicon detector to achieve good energy resolution and performance.

  2. Spectroscopy of unusual emission-line stars

    Science.gov (United States)

    Bopp, Bernard W.

    1988-01-01

    New spectroscopic observations are reported for ten stars that have been identified in the literature as having H-alpha emission with suspected F, G, or K spectral types. Three of the stars are shown to be BE stars, two are confirmed as early-type supergiants, three show composite (F or K + B) spectra, one is a 'post-T Tauri' star, and one is an ordinary F star without emission.

  3. Spatial calibration of a tokamak neutral beam diagnostic using in situ neutral beam emission

    Energy Technology Data Exchange (ETDEWEB)

    Chrystal, C. [Oak Ridge Associated Universities, Oak Ridge, Tennessee 37831 (United States); Burrell, K. H.; Pace, D. C. [General Atomics, P.O. Box 85608, San Diego, California 92186-5608 (United States); Grierson, B. A. [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543-0451 (United States)

    2015-10-15

    Neutral beam injection is used in tokamaks to heat, apply torque, drive non-inductive current, and diagnose plasmas. Neutral beam diagnostics need accurate spatial calibrations to benefit from the measurement localization provided by the neutral beam. A new technique has been developed that uses in situ measurements of neutral beam emission to determine the spatial location of the beam and the associated diagnostic views. This technique was developed to improve the charge exchange recombination (CER) diagnostic at the DIII-D tokamak and uses measurements of the Doppler shift and Stark splitting of neutral beam emission made by that diagnostic. These measurements contain information about the geometric relation between the diagnostic views and the neutral beams when they are injecting power. This information is combined with standard spatial calibration measurements to create an integrated spatial calibration that provides a more complete description of the neutral beam-CER system. The integrated spatial calibration results are very similar to the standard calibration results and derived quantities from CER measurements are unchanged within their measurement errors. The methods developed to perform the integrated spatial calibration could be useful for tokamaks with limited physical access.

  4. [Spectroscopy technique and ruminant methane emissions accurate inspecting].

    Science.gov (United States)

    Shang, Zhan-Huan; Guo, Xu-Sheng; Long, Rui-Jun

    2009-03-01

    The increase in atmospheric CH4 concentration, on the one hand through the radiation process, will directly cause climate change, and on the other hand, cause a lot of changes in atmospheric chemical processes, indirectly causing climate change. The rapid growth of atmospheric methane has gained attention of governments and scientists. All countries in the world now deal with global climate change as an important task of reducing emissions of greenhouse gases, but the need for monitoring the concentration of methane gas, in particular precision monitoring, can be scientifically formulated to provide a scientific basis for emission reduction measures. So far, CH4 gas emissions of different animal production systems have received extensive research. The methane emission by ruminant reported in the literature is only estimation. This is due to the various factors that affect the methane production in ruminant, there are various variables associated with the techniques for measuring methane production, the techniques currently developed to measure methane are unable to accurately determine the dynamics of methane emission by ruminant, and therefore there is an urgent need to develop an accurate method for this purpose. Currently, spectroscopy technique has been used and is relatively a more accurate and reliable method. Various spectroscopy techniques such as modified infrared spectroscopy methane measuring system, laser and near-infrared sensory system are able to achieve the objective of determining the dynamic methane emission by both domestic and grazing ruminant. Therefore spectroscopy technique is an important methane measuring technique, and contributes to proposing reduction methods of methane.

  5. 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.

  6. 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.

  7. 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...

  8. Absorption spectroscopy with sub-angstrom beams: ELS in STEM

    Science.gov (United States)

    Spence, John C. H.

    2006-03-01

    Electron-energy loss spectroscopy (EELS) performed using a modern transmission scanning electron microscope (STEM) now offers sub-nanometre spatial resolution and an energy resolution down to 200 meV or less, in favourable cases. The absorption spectra, which probe empty states, cover the soft x-ray region and may be obtained under conditions of well-defined momentum transfer (angle-resolved), providing a double projection onto crystallographic site and symmetry within the density of states. By combining the very high brightness of field-emission electron sources (brighter than a synchrotron) with the high cross-section of electron scattering, together with parallel detection (not possible with scanning x-ray absorption spectroscopy), a form of spectroscopy ideally suited to the study of nanostructures, interfacial states and defects in materials is obtained with uniquely high spatial resolution. We review the basic theory, the relationship of EELS to optical properties and the dielectric response function, the removal of multiple scattering artefacts and channelling effects. We consider applications in the light of recent developments in aberration corrector and electron monochromator design. Examples are cited of inner-shell spectra obtained from individual atoms within thin crystals, of the detection of interfacial electronic states in semiconductors, of inner-shell near edge structure mapped with sub-nanometre spatial resolution in glasses and of spectra obtained from individual carbon nanotubes, amongst many others.

  9. Emission Spectroscopy of the 4X Source Discharge With and Without N2 Gas

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Horace Vernon [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-01-14

    This tech note summarizes the December, 1988 emission spectroscopy measurements made on the 4X source discharge with and without N₂ gas added to the H + Cs discharge. This study is motivated by the desire to understand why small amounts of N₂ gas added to the source discharge results in a reduction in the H⁻ beam noise. The beneficial effect of N₂ gas on H⁻ beam noise was first discovered by Bill Ingalls and Stu Orbesen on the ATS SAS source. For the 4X source the observed effect is that when N2 gas is added to the discharge the H⁻ beam noise is reduced about a factor of 2.

  10. Plant species discrimination using emissive thermal infrared imaging spectroscopy

    Science.gov (United States)

    Rock, Gilles; Gerhards, Max; Schlerf, Martin; Hecker, Christoph; Udelhoven, Thomas

    2016-12-01

    Discrimination of plant species in the optical reflective domain is somewhat limited by the similarity of their reflectance spectra. Spectral characteristics in the visible to shortwave infrared (VSWIR) consist of combination bands and overtones of primary absorption bands, situated in the Thermal Infrared (TIR) region and therefore resulting in broad spectral features. TIR spectroscopy is assumed to have a large potential for providing complementary information to VSWIR spectroscopy. So far, in the TIR, plants were often considered featureless. Recently and following advances in sensor technology, plant species were discriminated based on specific emissivity signatures by Ullah et al. (2012) using directional-hemispherical reflectance (DHR) measurements in the laboratory. Here we examine if an accurate discrimination of plant species is equally possible using emissive thermal infrared imaging spectroscopy, an explicit spatial technique that is faster and more flexible than non-imaging measurements. Hyperspectral thermal infrared images were acquired in the 7.8⿿11.56 μm range at 40 nm spectral resolution (@10 μm) using a TIR imaging spectrometer (Telops HyperCam-LW) on seven plants each, of eight different species. The images were radiometrically calibrated and subjected to temperature and emissivity separation using a spectral smoothness approach. First, retrieved emissivity spectra were compared to laboratory reference spectra and then subjected to species discrimination using a random forest classifier. Second, classification results obtained with emissivity spectra were compared to those obtained with VSWIR reflectance spectra that had been acquired from the same leaf samples. In general, the mean emissivity spectra measured by the TIR imaging spectrometer showed very good agreement with the reference spectra (average Nash-Sutcliffe-Efficiency Index = 0.64). In species discrimination, the resulting accuracies for emissivity spectra are highly dependent on

  11. THE HYPHI PROJECT : HYPERNUCLEAR SPECTROSCOPY WITH STABLE HEAVY ION BEAMS AND RARE ISOTOPE BEAMS AT GSI AND FAIR

    NARCIS (Netherlands)

    Bianchin, S.; Achenbach, P.; Ajimura, S.; Borodina, O.; Fukuda, T.; Hoffmann, J.; Kavatsyuk, M.; Koch, K.; Koike, T.; Kurz, N.; Maas, F.; Minami, S.; Mizoi, Y.; Nagae, T.; Nakajima, D.; Okamura, A.; Ott, W.; Ozel, B.; Pochodzalla, J.; Rappold, C.; Saito, T. R.; Sakaguchi, A.; Sako, M.; Sekimoto, M.; Sugimura, H.; Takahashi, T.; Tamura, H.; Tanida, K.; Trautmann, W.

    2009-01-01

    The HypHI collaboration aims to perform a precise hypernuclear spectroscopy with stable heavy ion beams and rare isotope beams at GSI and FAIR in order to study hypernuclei at extreme isospin, especially neutron rich hypernuclei to look insight hyperon-nucleon interactions in the neutron rich medium

  12. Probing Local Environments by Time-Resolved Stimulated Emission Spectroscopy

    Directory of Open Access Journals (Sweden)

    Ana Rei

    2012-01-01

    Full Text Available Time-resolved stimulated emission spectroscopy was employed to probe the local environment of DASPMI (4-(4-(dimethylaminostyryl-N-methyl-pyridinium iodide in binary solvents of different viscosity and in a sol-gel matrix. DASPMI is one of the molecules of choice to probe local environments, and the dependence of its fluorescence emission decay on viscosity has been previously used for this purpose in biological samples, solid matrices as well as in solution. The results presented in this paper show that time-resolved stimulated emission of DASPMI is a suitable means to probe the viscosity of local environments. Having the advantage of a higher time resolution, stimulated emission can provide information that is complementary to that obtained from fluorescence decay measurements, making it feasible to probe systems with lower viscosity.

  13. Spectroscopy of an unusual emission line M star

    Science.gov (United States)

    Schneider, Donald P.; Greenstein, Jesse L.; Schmidt, Maarten; Gunn, James E.

    1991-01-01

    Moderate-resolution spectroscopy of an unusual late-type faint emission-line star, PC 0025 + 0047, is reported. A very strong (greater than 250 A equivalent width) an H-alpha emission line was detected by the present automated line search algorithm. The spectrum was found to have two unresolved emission lines (H-alpha and H-beta) near zero velocity, superposed on the absorption spectrum of a very red M dwarf which has strong K I, and relatively weak bands of TiO. From the weakness of the subordinate lines of Na I (8192 A) and other spectral features, it is inferred that it is definitely a cooler, and probably fainter, analog of LHS 2924. The strength of the emission lines indicates that PC 0025 + 0447 is very young and may be a fading predecessor brown drawf at an estimated M(bol) approaching 14m at a distance of about 60 pc.

  14. Bayesian electron density inference from JET lithium beam emission spectra using Gaussian processes

    CERN Document Server

    Kwak, Sehyun; Brix, M; Ghim, Y -c

    2016-01-01

    A Bayesian model to infer edge electron density profiles is developed for the JET lithium beam emission spectroscopy system, measuring Li I line radiation using 26 channels with ~1 cm spatial resolution and 10~20 ms temporal resolution. The density profile is modelled using a Gaussian process prior, and the uncertainty of the density profile is calculated by a Markov Chain Monte Carlo (MCMC) scheme. From the spectra measured by the transmission grating spectrometer, the Li line intensities are extracted, and modelled as a function of the plasma density by a multi-state model which describes the relevant processes between neutral lithium beam atoms and plasma particles. The spectral model fully takes into account interference filter and instrument effects, that are separately estimated, again using Gaussian processes. The line intensities are inferred based on a spectral model consistent with the measured spectra within their uncertainties, which includes photon statistics and electronic noise. Our newly devel...

  15. Secondary Electron Emission Beam Loss Monitor for LHC

    CERN Document Server

    Dehning, B; Holzer, E B; Kramer, Daniel

    2008-01-01

    Beam Loss Monitoring (BLM) system is a vital part of the active protection of the LHC accelerators' elements. It should provide the number of particles lost from the primary hadron beam by measuring the radiation field induced by their interaction with matter surrounding the beam pipe. The LHC BLM system will use ionization chambers as standard detectors but in the areas where very high dose rates are expected, the Secondary Emission Monitor (SEM) chambers will be employed because of their high linearity, low sensitivity and fast response. The SEM needs a high vacuum for proper operation and has to be functional for up to 20 years, therefore all the components were designed according to the UHV requirements and a getter pump was included. The SEM electrodes are made of Ti because of its Secondary Emission Yield (SEY) stability. The sensitivity of the SEM was modeled in Geant4 via the Photo-Absorption Ionization module together with custom parameterization of the very low energy secondary electron production. ...

  16. Emission Line Imaging and Spectroscopy of Distant Galaxies

    DEFF Research Database (Denmark)

    Zabl, Johannes Florian

    determinations even at lowest masses and highest redshifts. Finally, emission lines can be used in the first place to select large samples of galaxies at well defined redshifts through narrowband (NB) surveys, as the presence of a line in the NB filter raises the flux compared to that expected from the continuum...... for the gas surrounding a galaxy. Around some objects the extended Ly αemission is so strong that it can be detected for individual objects. In this thesis extremely deep VLT/XSHOOTER rest-frame far-UV spectroscopy is presented for Himiko, a gigantic Ly α emitter at redshift z = 6.6 or a time when...

  17. Electron beam generated whistler emissions in a laboratory plasma

    Science.gov (United States)

    Van Compernolle, B.; An, X.; Bortnik, J.; Thorne, R. M.; Pribyl, P.; Gekelman, W.

    2015-12-01

    Naturally occurring whistler mode emissions in the magnetosphere, are important since they are responsible for the acceleration of outer radiation belt electrons to relativistic energies and also for the scattering loss of these electrons into the atmosphere. Recently, we reported on the first laboratory experiment where whistler waves exhibiting fast frequency chirping have been artificially produced [1]. A beam of energetic electrons is launched into a cold plasma and excites both chirping whistler waves and broadband waves. Here we extend our previous analysis by comparing the properties of the broadband waves with linear theory.

  18. Electron beam generated whistler emissions in a laboratory plasma

    Energy Technology Data Exchange (ETDEWEB)

    Van Compernolle, B., E-mail: bvcomper@physics.ucla.edu; Pribyl, P.; Gekelman, W. [Department of Physics, University of California, Los Angeles (United States); An, X.; Bortnik, J.; Thorne, R. M. [Department of Atmospheric and Oceanic Sciences, University of California, Los Angeles (United States)

    2015-12-10

    Naturally occurring whistler mode emissions in the magnetosphere, are important since they are responsible for the acceleration of outer radiation belt electrons to relativistic energies and also for the scattering loss of these electrons into the atmosphere. Recently, we reported on the first laboratory experiment where whistler waves exhibiting fast frequency chirping have been artificially produced [1]. A beam of energetic electrons is launched into a cold plasma and excites both chirping whistler waves and broadband waves. Here we extend our previous analysis by comparing the properties of the broadband waves with linear theory.

  19. Electron Cyclotron Maser Emissions from Evolving Fast Electron Beams

    CERN Document Server

    Tang, J F; Chen, L; Zhao, G Q; Tan, C M

    2016-01-01

    Fast electron beams (FEBs) are common products of solar active phenomena. Solar radio bursts are an important diagnostic tool in the understanding of FEBs as well as the solar plasma environment in which they are propagating along solar magnetic fields. In particular, the evolutions of the energy spectrum and velocity distribution of FEBs due to the interaction with the ambient plasma and field when propagating can significantly influence the efficiency and property of their emissions. In this paper, we discuss some possible evolutions of the energy spectrum and velocity distribution of FEBs due to the energy loss processes and the pitch-angle effect caused by the magnetic field inhomogeneity, and analyze the effects of these evolutions on electron cyclotron maser (ECM) emission, which is one of the most important mechanisms of producing solar radio bursts by FEBs. The results show that the growth rates all decrease with the energy loss factor $Q$, but increase with the magnetic mirror ratio $\\sigma$ as well ...

  20. Monitoring corrosion in prestressed concrete beams using acoustic emission technique

    Science.gov (United States)

    ElBatanouny, Mohamed K.; Mangual, Jesé; Vélez, William; Ziehl, Paul H.; Matta, Fabio; González, Miguel

    2012-04-01

    Early detection of corrosion can help reduce the cost of maintenance and extend the service life of structures. Acoustic emission (AE) sensing has proven to be a promising method for early detection of corrosion in reinforced concrete members. A test program is presented composed of four medium-scale prestressed concrete T-beams. Three of the beams have a length of 16 ft. 4 in. (4.98 m), and one is 9 ft. 8 in. (2.95 m). In order to corrode the specimens a 3% NaCl solution was prepared, which is representative of sea salt concentration. The beams were subjected to wet-dry cycles to accelerate the corrosion process. Two of the specimens were pre-cracked prior to conditioning in order to examine the effect of crack presence. AE data was recorded continuously while half-cell potential measurements and corrosion rate by Linear Polarization Resistance (LPR) were measured daily. Corrosion current was also being acquired constantly to monitor any change in the concrete resistivity. Results indicate that the onset of corrosion may be identified using AE features, and were corroborated with measurements obtained from electrochemical techniques. Corroded areas were located using source triangulation. The results indicate that cracked specimens showed corrosion activity prior to un-cracked specimens and experienced higher corrosion rates. The level of corrosion was determined using corrosion rate results. Intensity analysis was used to link the corrosion rate and level to AE data.

  1. Hypernuclear Spectroscopy with Stable Heavy Ion Beams and Rare-isotope Beams:HypHI Project at GSI and FAIR

    Institute of Scientific and Technical Information of China (English)

    T.R.Saito

    2009-01-01

    The international HypHI collaboration proposes to perform hypernuclear spectroscopy with stable heavy ion beams and rare isotope beams at GSI and FAIR in order to study neutron and proton rich hypernuclei and to measure directly hypernuclear magnetic moments for the first time.The project is divided into four phases.In the first Phase 0 experiment,the feasibility of precise hypernuclear spectroscopy with heavy ion beams will be demonstrated by observing π~- decay channels of ~e_ΛH,~4_ΛH and ~5_ΛHe with ~6Li projectiles at 2 AGeV impinging on a ~(12)C target.In the later Phases 1 through 3,studies of proton and neutron rich hypernuclei,direct measurements of hypernuclear magnetic moments and the spectroscopy of hypernuclei toward the nucleon drip-lines are planned.

  2. Fluorescence-excitation and Emission Spectroscopy on Single FMO Complexes.

    Science.gov (United States)

    Löhner, Alexander; Ashraf, Khuram; Cogdell, Richard J; Köhler, Jürgen

    2016-08-22

    In green-sulfur bacteria sunlight is absorbed by antenna structures termed chlorosomes, and transferred to the RC via the Fenna-Matthews-Olson (FMO) complex. FMO consists of three monomers arranged in C3 symmetry where each monomer accommodates eight Bacteriochlorophyll a (BChl a) molecules. It was the first pigment-protein complex for which the structure has been determined with high resolution and since then this complex has been the subject of numerous studies both experimentally and theoretically. Here we report about fluorescence-excitation spectroscopy as well as emission spectroscopy from individual FMO complexes at low temperatures. The individual FMO complexes are subjected to very fast spectral fluctuations smearing out any possible different information from the ensemble data that were recorded under the same experimental conditions. In other words, on the time scales that are experimentally accessible by single-molecule techniques, the FMO complex exhibits ergodic behaviour.

  3. Absorption/emission spectroscopy and applications using shock tubes

    Science.gov (United States)

    Sulzmann, K. G. P.

    1988-09-01

    A historical overview is presented about the important contributions made by Penner, his co-workers, and his students to the application of shock-tube techniques for quantitative emission and absorption spectroscopy and its applications to chemical kinetics studies in high-temperature gases. The discussions address critical aspects related to valid determinations of quantitative spectroscopic data and chemical rate parameters and stress the requirements for uniformly heated gas samples, temperature determinations, gas-mixture preparations, selection of useful spectral intervals, verification of LTE conditions, time resolutions for concentration histories, uniqueness of kinetic measurements, as well as accuracies and reproducibilities of measurement results.The potential of absorption spectroscopy by molecule and/or radical resonance radiation and by laser transmission techniques is highlighted for kinetic studies in mixtures with very small reactant concentrations.Besides the work by the honoree and his school, the references include books, monographs and key articles related to the subjects discussed.

  4. Emission Spectroscopy of the Super-Earth 55 Cnc e

    Science.gov (United States)

    Dragomir, Diana; Bean, Jacob; Kreidberg, Laura; Stevenson, Kevin B.; Line, Michael R.

    2017-01-01

    Recent surveys have revealed an extraordinary and unexplained diversity of low-mass exoplanets. The main frontier for constraining the nature and origins of these planets is atmospheric characterization to reveal their detailed physical properties. Previous spectroscopic observations of small exoplanets have been focused on transmission measurements, but these studies are often limited by clouds. We are turning small exoplanet characterization in a new direction with multi-wavelength observations (Warm Spitzer and HST WFC3) of the dayside of 55 Cnc e, a quintessential super-Earth in a tight orbit and transiting a nearby star. We will present the first dayside emission spectrum of a super-Earth, which we use to distinguish between different atmospheric compositions and constrain the vertical temperature structure of the atmosphere. Our results for 55 Cnc e will guide JWST emission spectroscopy of a much larger sample of small close-in transiting exoplanets.

  5. Confocal microscopy with cylindrical vector beams and spectroscopy of single silicon nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Chizhik, Anna; Chizhik, Alexey; Baer, Sebastian; Meixner, Alfred [Inst. of Physical and Theor. Chem., Univ. of Tuebingen (Germany); Schmidt, Torsten; Huisken, Friedrich [Lab. Astrophys., Group of the MPI for Astronomy at the Inst. of Solid State Phys., Univ. of Jena (Germany)

    2010-07-01

    Being the paramount material silicon revealed new magnificent outlooks with the development of nanotechnology. During last years the research on silicon nanoparticles has been one of the hottest topics. However, many of their photoluminescence (PL) properties are still unclear. Combining the confocal microscopy, spectroscopy, and cylindrical vector beams (also known as higher order laser modes) we reveal new details of fundamental PL properties of Si/SiO{sub 2} core-shell systems and hollow SiO{sub 2} shells. We show that the emission from both systems may originate from defects of the SiO{sub 2} structure or at the Si-SiO{sub 2} interface. This result demonstrates the effect of ''break-down'' of the quantum confinement in small Si/SiO{sub 2} nanoparticles, which limits the PL tunability and thus, applications in Si optical nanostructures, especially in the short wavelength range. Using the technique of cylindrical vector beams we demonstrate that SiO{sub 2} nanoparticles and Si/SiO{sub 2} nanocrystals, where the PL originates from defects, possess linear transition dipole moment (TDM). Moreover, we precisely determine the 3-dimensional orientation of single nanoparticle TDM and show such dynamical effects as TDM sudden flipping.

  6. Microwaves spark emission spectroscopy for the analysis of cations: A simple form of atomic emission spectroscopy

    Institute of Scientific and Technical Information of China (English)

    Zahid Hussain; Khalid Mohammed Khan; Khadim Hussain; Sadam Hussain; Shahnaz Perveen

    2011-01-01

    A novel method for the cation analysis was investigated. The analysis is based on the sparking of the salts of metals in a microwave oven after placing in a graphite cell. The graphite cell absorbs microwaves and produces high temperature which converts the salt into light emitting species. The colour of light was found to dependent on the nature of cation, however, the intensity of the emitted light was found to be depending upon the form and shape of the graphite assembly in addition to the concentration of the salt. This communication presents explanation for all these observations and for the systematic and quantitative analysis using microwave spark emission technique.

  7. HYPERNUCLEAR SPECTROSCOPY WITH HEAVY ION BEAMS : THE HypHI PROJECT AT GSI AND FAIR

    NARCIS (Netherlands)

    Saito, T. R.; Bianchin, S.; Borodina, O.; Hoffmann, J.; Koch, K.; Kurz, N.; Maas, F.; Minami, S.; Nakajima, D.; Ott, W.; Oezel, B.; Rappold, C.; Schmidt, C.; Trautmann, W.; Traeger, M.; Voltz, S.; Achenbach, P.; Pochodzalla, J.; Sekimoto, M.; Takahashi, T.; Kavatsyuk, M.; Hayashi, Y.; Hiraiwa, T.; Moritsu, M.; Nagae, T.; Okamura, A.; Sako, M.; Sugimura, H.; Tanida, K.; Fukuda, T.; Mizoi, Y.; Ajimura, S.; Mochizuki, T.; Sakaguchi, A.; Koike, T.; Tamura, H.

    2010-01-01

    The HypHI experiment for precise hypernuclear spectroscopy with induced reactions of stable heavy ion beams and rare isotope beams is currently under preparation at GSI. The main goal of the HypHI project is to study neutron and proton rich hypernuclei and to measure directly hypernuclear magnetic m

  8. The HypHI project: Hypernuclear spectroscopy with stable heavy ion beams and rare isotope beams at GSI and FAIR

    CERN Document Server

    Bianchin, S; Ajimura, S; Borodina, O; Fukuda, T; Hoffmann, J; Kavatsyuk, M; Koch, K; Koike, T; Kurz, N; Maas, F; Minami, S; Mizoi, Y; Nagae, T; Nakajima, D; Okamura, A; Ott, W; Özel, B; Pochodzalla, J; Rappold, C; Saito, T R; Sakaguchi, A; Sako, M; Sekimoto, M; Sugimura, H; Takahashi, T; Tamura, H; Tanida, K; Trautmann, W

    2008-01-01

    The HypHI collaboration aims to perform a precise hypernuclear spectroscopy with stable heavy ion beams and rare isotope beams at GSI and fAIR in order to study hypernuclei at extreme isospin, especially neutron rich hypernuclei to look insight hyperon-nucleon interactions in the neutron rich medium, and hypernuclear magnetic moments to investigate baryon properties in the nuclei. We are currently preparing for the first experiment with $^6$Li and $^{12}$C beams at 2 AGeV to demonstrate the feasibility of a precise hypernuclear spectroscopy by identifying $^{3}_{\\Lambda}$H, $^{4}_{\\Lambda}$H and $^{5}_{\\Lambda}$He. The first physics experiment on these hypernuclei is planned for 2009. In the present document, an overview of the HypHI project and the details of this first experiment will be discussed.

  9. Quasi first-order Hermite Gaussian beam for enhanced sensitivity in Sagnac interferometer photothermal deflection spectroscopy.

    Science.gov (United States)

    Shiokawa, Naoyuki; Tokunaga, Eiji

    2016-05-30

    The detection sensitivity of a Sagnac interferometer photothermal deflection spectroscopy was enhanced by changing the probe beam pattern from zero-order to a quasi-first-order Hermite Gaussian (QHG) beam. The nature of the higher order HG mode, where the beam pattern is preserved during propagation with an increased field gradient, is utilized to enhance the measurement sensitivity. In this spectroscopy, the lateral beam deflection due to the photothermal effect is sensitively detected as a change in the interference light intensity. The change in intensity is amplified due to the higher field gradient of the QHG(1,0) beam at the photodetector. This amplification effect was both numerically and experimentally demonstrated to obtain twofold improvement in the signal-to-noise ratio.

  10. Single-Beam Coherent Raman Spectroscopy and Microscopy via Spectral Notch Shaping

    CERN Document Server

    Katz, Ori; Grinvald, Eran; Silberberg, Yaron

    2010-01-01

    Raman spectroscopy is one of the key techniques in the study of vibrational modes and molecular structures. In Coherent Anti-Stokes Raman Scattering (CARS) spectroscopy, a molecular vibrational spectrum is resolved via the third-order nonlinear interaction of pump, Stokes and probe photons, typically using a complex experimental setup with multiple beams and laser sources. Although CARS has become a widespread technique for label-free chemical imaging and detection of contaminants, its multi-source, multi-beam experimental implementation is challenging. In this work we present a simple and easily implementable scheme for performing single-beam CARS spectroscopy and microscopy using a single femtosecond pulse, shaped by a tunable narrowband notch filter. As a substitute for multiple sources, the single broadband pulse simultaneously provides the pump, Stokes and probe photons, exciting a broad band of vibrational levels. High spectroscopic resolution is obtained by utilizing a tunable spectral notch, shaped wi...

  11. LOW ENERGY BEAM-GAS SPECTROSCOPY OF HIGHLY IONISED ATOMS

    OpenAIRE

    Desesquelles, J.; DENIS A.; Druetta, M.; Martin, S.

    1989-01-01

    Features of low energy beam-gas spectroscopic source are reviewed and compared to those of other light sources. Measurement techniques are surveyed. They include the study of wavelength of heavy multiply charged ions in visible and u.v. ranges from normal excited states, doubly excited states, high n levels and doubly excited Rydberg levels.

  12. High-Directivity Emissions with Flexible Beam Numbers and Beam Directions Using Gradient-Refractive-Index Fractal Metamaterial

    OpenAIRE

    2014-01-01

    A three-dimensional (3D) highly-directive emission system is proposed to enable beam shaping and beam steering capabilities in wideband frequencies. It is composed of an omnidirectional source antenna and several 3D gradient-refractive-index (GRIN) lenses. To engineer a broadband impedance match, the design method for these 3D lenses is established under the scenario of free-space excitation by using a planar printed monopole. For realizations and demonstrations, a kind of GRIN metamaterial i...

  13. A compact atomic beam based system for Doppler-free laser spectroscopy of Strontium atoms

    OpenAIRE

    Verma, Gunjan; Vishwakarma, Chetan; Dharmadhikari, C. V.; Rapol, Umakant D.

    2016-01-01

    We report the construction of a simple, light weight and compact atomic beam spectroscopy cell for Strontium atoms. The cell is built using glass blowing technique and includes a simple Titanium Sublimation Pump for active pumping of the residual and background gases to maintain ultra-high vacuum. Commercially available and electrically heated dispenser source is used to generate the beam of Sr atoms. We perform spectroscopy on the $5s^2\\ ^1S_0\\longrightarrow 5s\\ 5p\\ ^1P_1$ transition to obta...

  14. Measurement of Moments and Radii of Light Nuclei by Collinear Fast-Beam Laser Spectroscopy and $\\beta$-NMR Spectroscopy

    CERN Document Server

    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. ...

  15. A Proposed Method for Measurement of Absolute Air Fluorescence Yield based on High Resolution Optical Emission Spectroscopy

    CERN Document Server

    Gika, V; Maltezos, S

    2016-01-01

    In this work, we present a method for absolute measurement of air fluorescence yield based on high resolution optical emission spectroscopy. The absolute measurement of the air fluorescence yield is feasible using the Cherenkov light, emitted by an electron beam simultaneously with the fluorescence light, as a "standard candle". The separation of these two radiations can be accomplished exploiting the "dark" spectral regions of the emission band systems of the molecular spectrum of nitrogen. In these "dark" regions the net Cherenkov light can be recorded experimentally and be compared with the calculated one. The instrumentation for obtaining the nitrogen molecular spectra in high resolution and the noninvasive method for monitoring the rotational temperature of the emission process are also described. For the experimental evaluation of the molecular spectra analysis we used DC normal glow discharges in air performed in an appropriate spectral lamp considered as an air-fluorescence light emulator. The propose...

  16. Bayesian electron density inference from JET lithium beam emission spectra using Gaussian processes

    Science.gov (United States)

    Kwak, Sehyun; Svensson, J.; Brix, M.; Ghim, Y.-C.; Contributors, JET

    2017-03-01

    A Bayesian model to infer edge electron density profiles is developed for the JET lithium beam emission spectroscopy (Li-BES) system, measuring Li I (2p-2s) line radiation using 26 channels with  ∼1 cm spatial resolution and 10∼ 20 ms temporal resolution. The density profile is modelled using a Gaussian process prior, and the uncertainty of the density profile is calculated by a Markov Chain Monte Carlo (MCMC) scheme. From the spectra measured by the transmission grating spectrometer, the Li I line intensities are extracted, and modelled as a function of the plasma density by a multi-state model which describes the relevant processes between neutral lithium beam atoms and plasma particles. The spectral model fully takes into account interference filter and instrument effects, that are separately estimated, again using Gaussian processes. The line intensities are inferred based on a spectral model consistent with the measured spectra within their uncertainties, which includes photon statistics and electronic noise. Our newly developed method to infer JET edge electron density profiles has the following advantages in comparison to the conventional method: (i) providing full posterior distributions of edge density profiles, including their associated uncertainties, (ii) the available radial range for density profiles is increased to the full observation range (∼26 cm), (iii) an assumption of monotonic electron density profile is not necessary, (iv) the absolute calibration factor of the diagnostic system is automatically estimated overcoming the limitation of the conventional technique and allowing us to infer the electron density profiles for all pulses without preprocessing the data or an additional boundary condition, and (v) since the full spectrum is modelled, the procedure of modulating the beam to measure the background signal is only necessary for the case of overlapping of the Li I line with impurity lines.

  17. Efficient regime of electromagnetic emission in a plasma with counterstreaming electron beams

    Energy Technology Data Exchange (ETDEWEB)

    Timofeev, I. V.; Annenkov, V. V. [Budker Institute of Nuclear Physics SB RAS and Novosibirsk State University, 630090 Novosibirsk (Russian Federation)

    2014-08-15

    Efficiency of electromagnetic emission produced in a magnetized plasma with counterstreaming electron beams was investigated using both the linear kinetic theory and particle-in-cell simulations. We calculated the growth rate of the beam-plasma instability taking into account both kinetic and relativistic effects and showed that there exists a regime in which transversely propagating electromagnetic waves can be generated by the coupling of the most unstable oblique beam-driven modes. It was confirmed by numerical simulations that such a tune-up of system parameters for a specific nonlinear process can lead to a substantial increase in electromagnetic emission efficiency. It was found that electromagnetic radiation emerging from the plasma in such a regime is generated near the harmonics of the pump frequency that is determined by the typical eigenfrequency of the beam-driven modes. It was also shown that the peak emission power can reach 5% of the maximal power lost by beam electrons.

  18. Efficient regime of electromagnetic emission in a plasma with counterstreaming electron beams

    Science.gov (United States)

    Timofeev, I. V.; Annenkov, V. V.

    2014-08-01

    Efficiency of electromagnetic emission produced in a magnetized plasma with counterstreaming electron beams was investigated using both the linear kinetic theory and particle-in-cell simulations. We calculated the growth rate of the beam-plasma instability taking into account both kinetic and relativistic effects and showed that there exists a regime in which transversely propagating electromagnetic waves can be generated by the coupling of the most unstable oblique beam-driven modes. It was confirmed by numerical simulations that such a tune-up of system parameters for a specific nonlinear process can lead to a substantial increase in electromagnetic emission efficiency. It was found that electromagnetic radiation emerging from the plasma in such a regime is generated near the harmonics of the pump frequency that is determined by the typical eigenfrequency of the beam-driven modes. It was also shown that the peak emission power can reach 5% of the maximal power lost by beam electrons.

  19. Detection of Bioaerosols Using Single Particle Thermal Emission Spectroscopy (First-year Report)

    Science.gov (United States)

    2012-02-01

    Detection of Bioaerosols using Single Particle Thermal Emission Spectroscopy (First-year Report) by Dr. Kristan P. Gurton, Melvin Felton, and...Research Laboratory Adelphi, MD 20783-1197 ARL-TR-5934 February 2012 Detection of Bioaerosols using Single Particle Thermal Emission...October 2011 4. TITLE AND SUBTITLE Detection of Bioaerosols using Single Particle Thermal Emission Spectroscopy (First-year Report) 5a. CONTRACT

  20. Simulations of electromagnetic emissions produced in a thin plasma by a continuously injected electron beam

    CERN Document Server

    Annenkov, V V; Volchok, E P

    2015-01-01

    In this paper, electromagnetic emissions produced in a thin beam-plasma system are studied using two-dimensional particle-in-cell simulations. For the first time, the problem of emission generation in such a system is considered in the realistic formulation allowing for the continuous injection of a relativistic electron beam through the plasma boundary. Specific attention is given to the thin plasma case in which the transverse plasma size is comparable to the typical wavelength of beam-driven oscillations. Such a case is often implemented in laboratory beam-plasma experiments and has a number of peculiarities. Emission from a thin plasma does not require intermediate generation of electromagnetic plasma eigenmodes, as in the infinite case, and is more similar to the regular antenna radiation. In this work, we determine how efficiently the fundamental and second harmonic emissions can be generated in previously modulated and initially homogeneous plasmas.

  1. Simulations of electromagnetic emissions produced in a thin plasma by a continuously injected electron beam

    Science.gov (United States)

    Annenkov, V. V.; Timofeev, I. V.; Volchok, E. P.

    2016-05-01

    In this paper, electromagnetic emissions produced in a thin beam-plasma system are studied using two-dimensional particle-in-cell simulations. For the first time, the problem of emission generation in such a system is considered in a realistic formulation allowing for the continuous injection of a relativistic electron beam through a plasma boundary. Specific attention is given to the thin plasma case in which the transverse plasma size is comparable to the typical wavelength of beam-driven oscillations. Such a case is often implemented in laboratory beam-plasma experiments and has a number of peculiarities. Emission from a thin plasma does not require intermediate generation of the electromagnetic plasma eigenmodes, as in an infinite case, and is more similar to the regular antenna radiation. In this work, we determine how efficiently the fundamental and the second harmonic emissions can be generated in previously modulated and initially homogeneous plasmas.

  2. Optical emission spectroscopy study on deposition process of microcrystalline silicon

    Institute of Scientific and Technical Information of China (English)

    Wu Zhi-Meng; Lei Qing-Song; Geng Xin-Hua; Zhao Ying; Sun Jian; Xi Jian-Ping

    2006-01-01

    This paper reports that the optical emission spectroscopy (OES) is used to monitor the plasma during the deposition process of hydrogenated microcrystalline silicon films in a very high frequency plasma enhanced chemical vapour deposition system. The OES intensities (SiH*, H*α and H*β) are investigated by varying the deposition parameters. The result shows that the discharge power, silane concentrations and substrate temperature affect the OES intensities. When the discharge power at silane concentration of 4% increases, the OES intensities increase first and then are constant, the intensities increase with the discharge power monotonously at silane concentration of 6%. The SiH* intensity increases with silane concentration, while the intensities of H*α and H*β increase first and then decrease. When the substrate temperature increases, the SiH* intensity decreases and the intensities of H*α and H*β are constant. The correlation between the intensity ratio of IH*α/ISiH* and the crystalline volume fraction (Xc) of films is confirmed.

  3. Investigating the effect of electron emission pattern on RF gun beam quality

    Energy Technology Data Exchange (ETDEWEB)

    Rajabi, A. [Laser and Plasma Research Institute, Shahid Beheshti University, G.C., Velenjak, 1983963113, Tehran (Iran, Islamic Republic of); Shokri, B., E-mail: b-shokri@sbu.ac.ir [Laser and Plasma Research Institute, Shahid Beheshti University, G.C., Velenjak, 1983963113, Tehran (Iran, Islamic Republic of); Physics Department, Shahid Beheshti University, G.C., Velenjak, 1983963113, Tehran (Iran, Islamic Republic of)

    2016-05-11

    Thermionic radio frequency gun is one of the most promising choices to gain a high quality electron beam, used in the infrared free electron lasers and synchrotron radiation injectors. To study the quality of the beam in a compact electron source, the emission pattern effect on the beam dynamics should be investigated. In the presented work, we developed a 3D simulation code to model the real process of thermionic emission and to investigate the effect of emission pattern, by considering geometrical constraints, on the beam dynamics. According to the results, the electron bunch emittance varies considerably with the emission pattern. Simulation results have been validated via comparison with the well-known simulation codes such as ASTRA simulation code and CST microwave studio, as well as other simulation results in the literature. It was also demonstrated that by using a continuous wave laser beam for heating the cathode, the emission pattern full width at half maximum (FWHM) of the transverse emission distribution is proportional to FWHM of the Gaussian profile for the laser beam. Additionally, by using the developed code, the effect of wall structure around the cathode on the back bombardment effect has been studied. According to the results, for a stable operation of the RF gun, one should consider the nose cone in vicinity of the cathode surface to reduce the back-bombardment effect. - Highlights: • We developed a 3D code to simulate the beam dynamics of thermionic RF gun. • Te impact of the emission pattern on the beam dynamic was investigated. • Different emission pattern results different emittance in the gun exit. • Using a nosecone around the cathode adjacent wall reduces back bombardment effect.

  4. Acoustic emission evaluation of reinforced concrete bridge beam with graphite composite laminate

    Science.gov (United States)

    Johnson, Dan E.; Shen, H. Warren; Finlayson, Richard D.

    2001-07-01

    A test was recently conducted on August 1, 2000 at the FHwA Non-Destructive Evaluation Validation Center, sponsored by The New York State DOT, to evaluate a graphite composite laminate as an effective form of retrofit for reinforced concrete bridge beam. One portion of this testing utilized Acoustic Emission Monitoring for Evaluation of the beam under test. Loading was applied to this beam using a two-point loading scheme at FHwA's facility. This load was applied in several incremental loadings until the failure of the graphite composite laminate took place. Each loading culminated by either visual crack location or large audible emissions from the beam. Between tests external cracks were located visually and highlighted and the graphite epoxy was checked for delamination. Acoustic Emission data was collected to locate cracking areas of the structure during the loading cycles. To collect this Acoustic Emission data, FHwA and NYSDOT utilized a Local Area Monitor, an Acoustic Emission instrument developed in a cooperative effort between FHwA and Physical Acoustics Corporation. Eight Acoustic Emission sensors were attached to the structure, with four on each side, in a symmetrical fashion. As testing progressed and culminated with beam failure, Acoustic Emission data was gathered and correlated against time and test load. This paper will discuss the analysis of this test data.

  5. Development of a Reference Database for Particle-Induced Gamma-ray Emission spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Dimitriou, P., E-mail: P.Dimitriou@iaea.org [International Atomic Energy Agency, Wagramerstrasse 5, A-1400 Vienna (Austria); Becker, H.-W. [Ruhr Universität Bochum, Gebäude NT05/130, Postfach 102148, Bochum 44721 (Germany); Bogdanović-Radović, I. [Department of Experimental Physics, Institute Rudjer Boskovic, Bijenicka Cesta 54, 10000 Zagreb (Croatia); Chiari, M. [Istituto Nazionale di Fisica Nucleare, Via Sansone 1, Sesto Fiorentino, 50019 Firenze (Italy); Goncharov, A. [Kharkov Institute of Physics and Technology, National Science Center, Akademicheskaya Str.1, Kharkov 61108 (Ukraine); Jesus, A.P. [Departamento de Física, Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa (Portugal); Kakuee, O. [Nuclear Science and Technology Research Institute, End of North Karegar Ave., PO Box 14395-836, Tehran (Iran, Islamic Republic of); Kiss, A.Z. [Institute of Nuclear Research (ATOMKI), Bem ter 18/c, PO Box 51, 4001 Debrecen (Hungary); Lagoyannis, A. [National Center of Scientific Research “Demokritos”, Agia Paraskevi, P.O. Box 60228, 15310 Athens (Greece); Räisänen, J. [Division of Materials Physics, Department of Physics, University of Helsinki, PO Box 43, 00014 University of Helsinki (Finland); Strivay, D. [Institut de Physique Nucleaire, Atomique et de Spectroscopie, Universite de Liège, Sart Tilman, B15 4000 Liège (Belgium); Zucchiatti, A. [Centro de Micro Análisis de Materiales, Universidad Autónoma de Madrid, Faraday 3, Madrid 28049 (Spain)

    2016-03-15

    Particle-Induced Gamma-ray Emission (PIGE) is a powerful analytical technique that exploits the interactions of rapid charged particles with nuclei located near a sample surface to determine the composition and structure of the surface regions of solids by measurement of characteristic prompt γ rays. The potential for depth profiling of this technique has long been recognized, however, the implementation has been limited owing to insufficient knowledge of the physical data and lack of suitable user-friendly computer codes for the applications. Although a considerable body of published data exists in the nuclear physics literature for nuclear reaction cross sections with γ rays in the exit channel, there is no up-to-date, comprehensive compilation specifically dedicated to IBA applications. A number of PIGE cross-section data had already been uploaded to the Ion Beam Analysis Nuclear Data Library (IBANDL) ( (http://www-nds.iaea.org/ibandl)) by members of the IBA community by 2011, however a preliminary survey of this body of unevaluated experimental data has revealed numerous discrepancies beyond the uncertainty limits reported by the authors. Using the resources and coordination provided by the IAEA, a concerted effort to improve the situation was made within the Coordinated Research Project on the Development of a Reference Database for PIGE spectroscopy, from 2011 to 2015. The aim of the CRP was to create a data library for Ion Beam Analysis that contains reliable and usable data on charged particle γ-ray emission cross sections that would be made freely available to the user community. As the CRP has reached its completion, we shall present its main achievements, including the results of nuclear cross-section evaluations and the development of a computer code that will become available to the public allowing for the implementation of a standardless PIGE technique.

  6. High-resolution electron collision spectroscopy with multicharged ions in merged beams

    Energy Technology Data Exchange (ETDEWEB)

    Lestinsky, M.

    2007-04-18

    The Heidelberg ion storage ring Tsr is currently the only ring equipped with two independent devices for the collinear merging of a cold electron beam with stored ions. This greatly improves the potential of electron-ion collision experiments, as the ion beam can be cooled with one electron beam, while the other one is used as a dedicated target for energy-resolved electron collision processes, such as recombination. The work describes the implementation of this system for rst electron collision spectroscopy experiments. A detection system has been realized including an ion detector and specroscopic beam-control software and instrumentation. Moreover, in order to improve the spectroscopic resolution systematical studies of intrinsic relaxation processes in the electron beam have been carried out. These include the dependence on the electron beam density, the magnetic guiding eld strength, and the acceleration geometry. The recombination measurements on low-lying resonances in lithiumlike Sc{sup 18+} yield a high-precision measurement of the 2s-2p{sub 3/2} transition energy in this system. Operation of the two-electron-beam setup at high collision energy ({approx}1000 eV) is established using resonances of hydrogenlike Mg{sup 11+}, while the unique possibility of modifying the beam-merging geometry con rms its importance for the electron-ion recombination rate at lowest relative energy, as demonstrated on F{sup 6+}. (orig.)

  7. Temporal structure of double plasma frequency emission of thin beam-heated plasma

    Energy Technology Data Exchange (ETDEWEB)

    Postupaev, V. V.; Ivanov, I. A.; Arzhannikov, A. V.; Vyacheslavov, L. N. [Budker Institute of Nuclear Physics, 11 Lavrentjev Avenue, 630090 Novosibirsk (Russian Federation); Novosibirsk State University, 2 Pirogova st., 630090 Novosibirsk (Russian Federation); Burdakov, A. V.; Polosatkin, S. V. [Budker Institute of Nuclear Physics, 11 Lavrentjev Avenue, 630090 Novosibirsk (Russian Federation); Novosibirsk State Technical University, 20 Karl Marks Avenue, 630092 Novosibirsk (Russian Federation); Sklyarov, V. F.; Gavrilenko, D. Ye.; Kandaurov, I. V.; Kurkuchekov, V. V.; Mekler, K. I.; Popov, S. S.; Rovenskikh, A. F.; Sudnikov, A. V.; Sulyaev, Yu. S.; Trunev, Yu. A. [Budker Institute of Nuclear Physics, 11 Lavrentjev Avenue, 630090 Novosibirsk (Russian Federation); Kasatov, A. A. [Novosibirsk State University, 2 Pirogova st., 630090 Novosibirsk (Russian Federation)

    2013-09-15

    In the work presented here dynamics of spiky microwave emission of a beam-heated plasma near the double plasma frequency in ∼100 GHz band was studied. The plasma is heated by 80 keV, ∼2 MW, sub-ms electron beam that is injected into the multiple-mirror trap GOL-3. The beam-heated plasma diameter is of the order of the emitted wavelength. Modulation of individual emission spikes in the microwave radiation is found. The radiation dynamics observed can be attributed to a small number of compact emitting zones that are periodically distorted.

  8. Study of a high power hydrogen beam diagnostic based on secondary electron emission

    Science.gov (United States)

    Sartori, E.; Panasenkov, A.; Veltri, P.; Serianni, G.; Pasqualotto, R.

    2016-11-01

    In high power neutral beams for fusion, beam uniformity is an important figure of merit. Knowing the transverse power profile is essential during the initial phases of beam source operation, such as those expected for the ITER heating neutral beam (HNB) test facility. To measure it a diagnostic technique is proposed, based on the collection of secondary electrons generated by beam-surface and beam-gas interactions, by an array of positively biased collectors placed behind the calorimeter tubes. This measurement showed in the IREK test stand good proportionality to the primary beam current. To investigate the diagnostic performances in different conditions, we developed a numerical model of secondary electron emission, induced by beam particle impact on the copper tubes, and reproducing the cascade of secondary emission caused by successive electron impacts. The model is first validated against IREK measurements. It is then applied to the HNB case, to assess the locality of the measurement, the proportionality to the beam current density, and the influence of beam plasma.

  9. The field emission properties of high aspect ratio diamond nanocone arrays fabricated by focused ion beam milling

    Directory of Open Access Journals (Sweden)

    Z.L. Wang, Q. Wang, H.J. Li, J.J. Li, P. Xu, Q. Luo, A.Z. Jin, H.F. Yang and C.Z. Gu

    2005-01-01

    Full Text Available High aspect ratio diamond nanocone arrays are formed on freestanding diamond film by means of focused ion beam (FIB milling technology and hot-filament chemical vapor deposition (HFCVD method. The structure and phase purity of an individual diamond nanocone are characterized by scanning electron microscopy (SEM and micro-Raman spectroscopy. The result indicates that the diamond cones with high aspect ratio and small tip apex radius can be obtained by optimizing the parameters of FIB milling and diamond growth. The diamond nanocone arrays were also used to study the electron field emission properties and electric field shielding effect, finding high emission current density, low threshold and weak shielding effect, all attributable to the high field enhancement factor and suitable cone density of the diamond nanocone emitter

  10. Molecular Beam Optical Zeeman Spectroscopy of Vanadium Monoxide, VO

    Science.gov (United States)

    Nguyen, Trung; Zhang, Ruohan; Steimle, Timothy

    2016-06-01

    Like almost all astronomical studies, exoplanet investigations are observational endeavors that rely primarily on remote spectroscopic sensing to infer the physical properties of planets. Most exoplanet related information is inferred from to temporal variation of luminosity of the parent star. An effective method of monitoring this variation is via Magnetic Doppler Imaging (MDI), which uses optical polarimetry of paramagnetic molecules or atoms. One promising paramagnetic stellar absorption is the near infrared spectrum of VO. With this in mind, we have begun a project to record and analyze the field-free and Zeeman spectrum of the band. A cold (approx. 20 K) beam of VO was probed with a single frequency laser and detected using laser induced fluorescence. The determined spectral parameters will be discussed and compared to those extracted from the analysis of a hot spectrum. Supported by the National Science Foundation under the Grant No. CHE-1265885. O. Kochukhov, N. Rusomarov, J. A. Valenti, H. C. Stempels, F. Snik, M. Rodenhuis, N. Piskunov, V. Makaganiuk, C. U. Keller and C. M. Johns-Krull, Astron. Astrophys. 574 (Pt. 2), A79/71-A79/12 (2015). S. V. Berdyugina, Astron. Soc. Pac. Conf. Ser. 437 (Solar Polarization 6), 219-235 (2011). S. V. Berdyugina, P. A. Braun, D. M. Fluri and S. K. Solanki, Astron. Astrophys. 444 (3), 947-960 (2005). A. S. C. Cheung, P. G. Hajigeorgiou, G. Huang, S. Z. Huang and A. J. Merer, J. Mol. Spectrosc. 163 (2), 443-458 (1994)

  11. High-Directivity Emissions with Flexible Beam Numbers and Beam Directions Using Gradient-Refractive-Index Fractal Metamaterial

    Science.gov (United States)

    Xu, He-Xiu; Wang, Guang-Ming; Tao, Zui; Cui, Tie Jun

    2014-01-01

    A three-dimensional (3D) highly-directive emission system is proposed to enable beam shaping and beam steering capabilities in wideband frequencies. It is composed of an omnidirectional source antenna and several 3D gradient-refractive-index (GRIN) lenses. To engineer a broadband impedance match, the design method for these 3D lenses is established under the scenario of free-space excitation by using a planar printed monopole. For realizations and demonstrations, a kind of GRIN metamaterial is proposed, which is constructed by non-uniform fractal geometries. Due to the non-resonant and deep-subwavelength features of the fractal elements, the resulting 3D GRIN metamaterial lenses have extra wide bandwidth (3 to 7.5 GHz), and are capable of manipulating electromagnetic wavefronts accurately, advancing the state of the art of available GRIN lenses. The proposal for the versatile highly-directive emissions has been confirmed by simulations and measurements, showing that not only the number of beams can be arbitrarily tailored but also the beam directions can be steerable. The proposal opens a new way to control broadband highly-directive emissions with pre-designed directions, promising great potentials in modern wireless communication systems. PMID:25034268

  12. Transmittance, Reflectance, and Emission Spectroscopy of Meteorites from the UV to the IR Spectral Range

    Science.gov (United States)

    Maturilli, A.; Helbert, J.; Koulen, J. M.; Ferrari, S.; Martellato, E.

    2016-08-01

    Transmittance, reflectance, and emissivity Spectra of six meteorites have been collected at the Planetary Spectroscopy Laboratory (PSL) of DLR in Berlin in the whole spectral range from the UV to the IR.

  13. 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. ...

  14. Study on the effect of beam propagation through atmospheric turbulence on standoff nanosecond laser induced breakdown spectroscopy measurements.

    Science.gov (United States)

    Laserna, J J; Reyes, R Fernández; González, R; Tobaria, L; Lucena, P

    2009-06-08

    We report on an experimental study of the effect of atmospheric turbulence on laser induced breakdown spectroscopy (LIBS) measurements. The characteristics of the atmosphere dictate specific performance constraints to this technology. Unlike classical laboratory LIBS systems where the distance to the sample is well known and characterized, LIBS systems working at several tens of meters to the target have specific atmospheric propagation conditions that cause the quality of the LIBS signals to be affected to a significant extent. Using a new LIBS based sensor system fitted with a nanosecond laser emitting at 1064 nm, propagation effects at distances of up to 120 m were investigated. The effects observed include wander and scintillation in the outgoing laser beam and in the return atomic emission signal. Plasmas were formed on aluminium targets. Average signal levels and signal fluctuations are measured so the effect of atmospheric turbulence on LIBS measurements is quantified.

  15. Analysis of quantum semiconductor heterostructures by ballistic electron emission spectroscopy

    Science.gov (United States)

    Guthrie, Daniel K.

    1998-09-01

    The microelectronics industry is diligently working to achieve the goal of gigascale integration (GSI) by early in the 21st century. For the past twenty-five years, progress toward this goal has been made by continually scaling down device technology. Unfortunately, this trend cannot continue to the point of producing arbitrarily small device sizes. One possible solution to this problem that is currently under intensive study is the relatively new area of quantum devices. Quantum devices represent a new class of microelectronic devices that operate by utilizing the wave-like nature (reflection, refraction, and confinement) of electrons together with the laws of quantum mechanics to construct useful devices. One difficulty associated with these structures is the absence of measurement techniques that can fully characterize carrier transport in such devices. This thesis addresses this need by focusing on the study of carrier transport in quantum semiconductor heterostructures using a relatively new and versatile measurement technique known as ballistic electron emission spectroscopy (BEES). To achieve this goal, a systematic approach that encompasses a set of progressively more complex structures is utilized. First, the simplest BEES structure possible, the metal/semiconductor interface, is thoroughly investigated in order to provide a foundation for measurements on more the complex structures. By modifying the semiclassical model commonly used to describe the experimental BEES spectrum, a very complete and accurate description of the basic structure has been achieved. Next, a very simple semiconductor heterostructure, a Ga1-xAlxAs single-barrier structure, was measured and analyzed. Low-temperature measurements on this structure were used to investigate the band structure and electron-wave interference effects in the Ga1-xAlxAs single barrier structure. These measurements are extended to a simple quantum device by designing, measuring, and analyzing a set of

  16. Absorption and emission spectroscopy in natural and synthetic corundum

    Science.gov (United States)

    Spinolo, G.; Palanza, V.; Ledonne, A.; Paleari, A.

    2009-04-01

    In the frame of an extensive project on the optical characterization of the many varieties of corundum (see:www.gemdata.mater.unimib.it ) we reconsidered the current interpretation of the absorption spectra with particular attention to the bands attributed to the IVCT mechanism Fe2+→ Fe3+ and Fe2+→Ti4+. A detailed study was devoted to natural metamorphic and Verneuil synthetic pale blue sapphires . In that paper (I.Fontana et al 2008) we gave experimental evidence that the band at 17500 cm-1 often attributed to Fe2+→Ti4+ IVCT transitions is in reality due to the 4T2 crystal field transition of Cr3+ partially overlapped by the 2E of Ti3+. The results of radio and photoluminescence excitation experiments obtained there, led us to propose that the color of these sapphires is mainly due to Cr in its two valence states ; Ti 3+ and Fe3+ have a minor role. After those encouraging results, we decided to apply the same approach to the study of deep blue and yellow sapphires of magmatic origin. Evaluation of impurity ion concentration by EDXRF revealed that in all these samples the concentration of Fe is quite high (around 1%) while Cr and Ti are barely detectable. Characteristic of the absorption spectra of deep blue samples is the dominant presence of the 5E spin allowed transition of Fe2+; Fe3+ has a minor role due to the fact that all d5 transitions are spin forbidden and ,consequently, very weak. In yellow sapphires Fe is totally in its 3+ valence state. In these cases, the color from yellow to blue, sometimes even within the same sample, depends. on oxidizing or reducing growth conditions. Even if the concentrations of Cr and Ti are very low, their characteristic emissions are the only ones observable down to 10000 cm-1 in radio and photoluminescence spectra. This piece of evidence suggested us to propose for the absorption bands present in the 14000 to 21000 cm-1 range, often attributed to IVCT, the same attribution given to the analogous bands in metamorphic

  17. Practical Entangled-Photon Virtual-State Spectroscopy using Intense Twin Beams

    CERN Document Server

    Svozilík, Jiří; León-Montiel, Roberto de J

    2016-01-01

    We propose a new practical approach towards ultrasensitive measurements in chemical and biological systems based on the so-called virtual-state spectroscopy technique. The proposed scheme makes use of intense twin beams generated by pump pulses with different frequency chirps to successfully extract information about the virtual states that contribute to the two-photon excitation of an absorbing medium. Interestingly, we show that our approach may enable entangled-photon absorption rates up to four orders of magnitude larger than previously reported. Because of its simplicity, our method paves the way towards the first experimental implementation of the virtual-state spectroscopy technique.

  18. Practical Entangled-Photon Virtual-State Spectroscopy using Intense Twin Beams

    OpenAIRE

    2016-01-01

    We propose a new practical approach towards ultrasensitive measurements in chemical and biological systems based on the so-called virtual-state spectroscopy technique. The proposed scheme makes use of intense twin beams generated by pump pulses with different frequency chirps to successfully extract information about the virtual states that contribute to the two-photon excitation of an absorbing medium. Interestingly, we show that our approach may enable entangled-photon absorption rates up t...

  19. X-ray emission as a diagnostic from pseudospark-sourced electron beams

    Energy Technology Data Exchange (ETDEWEB)

    Bowes, D., E-mail: david.bowes@strath.ac.uk [Department of Physics, SUPA, University of Strathclyde, Glasgow G4 0NG (United Kingdom); Yin, H.; He, W.; Zhang, L.; Cross, A.W.; Ronald, K.; Phelps, A.D.R. [Department of Physics, SUPA, University of Strathclyde, Glasgow G4 0NG (United Kingdom); Chen, D.; Zhang, P. [Computed Tomography Lab, School of Mathematical Sciences, Capital Normal University, Beijing 100048 (China); Chen, X.; Li, D. [Department of Electronic Engineering, Queen Mary University of London, London E1 4NS (United Kingdom)

    2014-09-15

    X-ray emission has been achieved using an electron beam generated by a pseudospark low-pressure discharge and utilised as a diagnostic for beam detection. A 300 A, 34 kV PS-sourced electron beam pulse of 3 mm diameter impacting on a 0.1 mm-thick molybdenum target generated X-rays which were detected via the use of a small, portable X-ray detector. Clear X-ray images of a micro-sized object were captured using an X-ray photodetector. This demonstrates the inducement of proton induced X-ray emission (PIXE) not only as an indicator of beam presence but also as a future X-ray source for small-spot X-ray imaging of materials.

  20. Simulations of Field-Emission Electron Beams from CNT Cathodes in RF Photoinjectors

    Energy Technology Data Exchange (ETDEWEB)

    Mihalcea, Daniel [NIU, DeKalb; Faillace, Luigi [RadiaBeam Tech.; Panuganti, Harsha [NIU, DeKalb; Thangaraj, Jayakar C.T. [Fermilab; Piot, Philippe [NIU, DeKalb

    2015-06-01

    Average field emission currents of up to 700 mA were produced by Carbon Nano Tube (CNT) cathodes in a 1.3 GHz RF gun at Fermilab High Brightness Electron Source Lab. (HBESL). The CNT cathodes were manufactured at Xintek and tested under DC conditions at RadiaBeam. The electron beam intensity as well as the other beam properties are directly related to the time-dependent electric field at the cathode and the geometry of the RF gun. This report focuses on simulations of the electron beam generated through field-emission and the results are compared with experimental measurements. These simulations were performed with the time-dependent Particle In Cell (PIC) code WARP.

  1. Quantitative Assessment of Amino Acid Damage upon keV Ion Beam Irradiation Through FTIR Spectroscopy

    Science.gov (United States)

    Huang, Qing; Ke, Zhigang; Su, Xi; Yuan, Hang; Zhang, Shuqing; Yu, Zengliang

    2010-06-01

    Ion beam irradiation induces important biological effects and it is a long-standing task to acquire both qualitative and quantitative assessment of these effects. One effective way in the investigation is to utilize Fourier transformation infrared (FTIR) spectroscopy because it can offer sensitive and non-invasive measurements. In this paper a novel protocol was employed to prepare biomolecular samples in the form of thin and transversely uniform solid films that were suitable for both infrared and low-energy ion beam irradiation experiments. Under the irradiation of N+ and Ar+ ion beams of 25 keV with fluence ranging from 5×1015 ions/cm2 to 2.5×10 ions/cm2, the ion radio-sensitivity of four amino acids, namely, glycine, tyrosine, methionine and phenylalanine, were evaluated and compared. The ion beam irradiation caused biomolecular decomposition accompanied by molecular desorption of volatile species and the damage was dependent on ion type, fluence, energy and types of amino acids. The effectiveness of application of FTIR spectroscopy to the quantitative assessment of biomolecular damage dose effect induced by low-energy ion radiation was thus demonstrated.

  2. Electron beam induced THz emissions from nanotube array

    Science.gov (United States)

    Kumar, Ashok; Kumar, Pawan

    2016-10-01

    A new scheme of terahertz radiation generation by passing an ultrashort electron bunch over a planar array of nanotube/nanorod across their lengths is proposed and analyzed. The beam pulse exerts a repulsive impulse on the free electron cylinder of each nanorod and displaces them with respect to ion cylinder. After the passage of the pulse, the electron cylinders oscillate at their natural frequency ω p / √{ 2 } (where ω p is the plasma frequency of electrons in each carbon nanotube) acting as phased array dipole antennae, emitting THz radiation.

  3. Thermal Emissivity-Based Chemical Spectroscopy through Evanescent Tunneling.

    Science.gov (United States)

    Poole, Zsolt L; Ohodnicki, Paul R

    2016-04-01

    A new spectroscopic technique is presented, with which environmentalchemistry-induced thermal emissivity changes of thin films are extracted with high isolation through evanescent tunneling. With this method the hydrogen-induced emissivity changes of films of TiO2 , Pd-TiO2 , and Au-TiO2 , with properties of high conductivity, hydrogen chemisorption, and plasmonic activity, are characterized in the UV-vis and NIR wavelength ranges, at 1073 K.

  4. Transmission And Emission Spectroscopy Of Exoplanetary Atmospheres From The Ground

    Science.gov (United States)

    Waldmann, Ingo

    2010-01-01

    It has been shown in recent years with great success that spectroscopy of exoplanetary atmospheres is feasible using space based observatories such as the HST and Spitzer. However, with the end of the Spitzer cold-phase, space based observations in the near to mid infra-red are limited, which will remain true until the the onset of the JWST. The importance of developing methods of ground based spectroscopic analysis of known hot Jupiters is therefore apparent. In the past, various groups have attempted exoplanetary spectroscopy using ground based facilities and various techniques. Here I like to present some preliminary results on a new attempt of the ground based efforts and discuss the feasibility of ground-based spectroscopy of exoplanetary atmospheres. This project is under the supervision of Giovanna Tinetti (University College London) and in collaboration with J. P. Beaulieu (Institut d'Astrophysique de Paris), Mark Swain and Pieter Deroo (Jet Propulsion Laboratory, Caltech).

  5. Cascade emission in electron beam ion trap plasma of W$^{25+}$ ion

    CERN Document Server

    Jonauskas, V; Kučas, S; Masys, Š; Kynienė, A; Gaigalas, G; Kisielius, R; Radžiūtė, L; Rynkun, P; Merkelis, G

    2015-01-01

    Spectra of the W$^{25+}$ ion are studied using the collisional-radiative model (CRM) with an ensuing cascade emission. It is determined that the cascade emission boosts intensities only of a few lines in the $10 - 3$ nm range. The cascade emission is responsible for the disappearance of structure of lines at about 6 nm in the electron beam ion trap plasma. Emission band at 4.5 to 5.3 nm is also affected by the cascade emission. The strongest lines in the CRM spectrum correspond to $4d^{9} 4f^{4} \\rightarrow 4f^{3}$ transitions, while $4f^{2} 5d \\rightarrow 4f^{3}$ transitions arise after the cascade emission is taken into account.

  6. INSIDE in-beam positron emission tomography system for particle range monitoring in hadrontherapy.

    Science.gov (United States)

    Bisogni, Maria Giuseppina; Attili, Andrea; Battistoni, Giuseppe; Belcari, Nicola; Camarlinghi, Niccolo'; Cerello, Piergiorgio; Coli, Silvia; Del Guerra, Alberto; Ferrari, Alfredo; Ferrero, Veronica; Fiorina, Elisa; Giraudo, Giuseppe; Kostara, Eleftheria; Morrocchi, Matteo; Pennazio, Francesco; Peroni, Cristiana; Piliero, Maria Antonietta; Pirrone, Giovanni; Rivetti, Angelo; Rolo, Manuel D; Rosso, Valeria; Sala, Paola; Sportelli, Giancarlo; Wheadon, Richard

    2017-01-01

    The quality assurance of particle therapy treatment is a fundamental issue that can be addressed by developing reliable monitoring techniques and indicators of the treatment plan correctness. Among the available imaging techniques, positron emission tomography (PET) has long been investigated and then clinically applied to proton and carbon beams. In 2013, the Innovative Solutions for Dosimetry in Hadrontherapy (INSIDE) collaboration proposed an innovative bimodal imaging concept that combines an in-beam PET scanner with a tracking system for charged particle imaging. This paper presents the general architecture of the INSIDE project but focuses on the in-beam PET scanner that has been designed to reconstruct the particles range with millimetric resolution within a fraction of the dose delivered in a treatment of head and neck tumors. The in-beam PET scanner has been recently installed at the Italian National Center of Oncologic Hadrontherapy (CNAO) in Pavia, Italy, and the commissioning phase has just started. The results of the first beam test with clinical proton beams on phantoms clearly show the capability of the in-beam PET to operate during the irradiation delivery and to reconstruct on-line the beam-induced activity map. The accuracy in the activity distal fall-off determination is millimetric for therapeutic doses.

  7. High-Resolution X-ray Emission and X-ray Absorption Spectroscopy

    OpenAIRE

    de Groot, F. M. F.

    2001-01-01

    In this review, high-resolution X-ray emission and X-ray absorption spectroscopy will be discussed. The focus is on the 3d transition-metal systems. To understand high-resolution X-ray emission and reso-nant X-ray emission, it is first necessary to spend some time discussing the X-ray absorption process. Section II discusses 1s X-ray absorption, i.e., the K edges, and section III deals with 2p X-ray absorption, the L edges. X-ray emission is discussed in, respectively, the L edges. X-ray emis...

  8. Non-coincident multi-wavelength emission absorption spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Baumann, L.E.

    1995-02-01

    An analysis is presented of the effect of noncoincident sampling on the measurement of atomic number density and temperature by multiwavelength emission absorption. The assumption is made that the two signals, emission and transmitted lamp, are time resolved but not coincident. The analysis demonstrates the validity of averages of such measurements despite fluctuations in temperature and optical depth. At potassium-seeded MHD conditions, the fluctuations introduce additional uncertainty into measurements of potassium atom number density and temperature but do not significantly bias the average results. Experimental measurements in the CFFF aerodynamic duct with coincident and noncoincident sampling support the analysis.

  9. Generation of powerful terahertz emission in a beam-driven strong plasma turbulence

    CERN Document Server

    Arzhannikov, A V

    2012-01-01

    Generation of terahertz electromagnetic radiation due to coalescence of upper-hybrid waves in the long-wavelength region of strong plasma turbulence driven by a high-current relativistic electron beam in a magnetized plasma is investigated. The width of frequency spectrum as well as angular characteristics of this radiation for various values of plasma density and turbulence energy are calculated using the simple theoretical model adequately describing beam-plasma experiments at mirror traps. It is shown that the power density of electromagnetic emission at the second harmonic of plasma frequency in the terahertz range for these laboratory experiments can reach the level of 1 ${MW/cm}^3$ with 1% conversion efficiency of beam energy losses to electromagnetic emission.

  10. MINOS: A vertex tracker coupled to a thick liquid-hydrogen target for in-beam spectroscopy of exotic nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Obertelli, A.; Delbart, A.; Anvar, S.; Audirac, L.; Authelet, G.; Bruyneel, B.; Calvet, D.; Chateau, F.; Corsi, A.; Gheller, J.M.; Giganon, A.; Lahonde-Hamdoun, C.; Leboeuf, D.; Loiseau, D.; Mohamed, A.; Mols, J.P.; Peron, C.; Peyaud, A.; Pollacco, E.C.; Prono, G.; Rousse, J.Y.; Santamaria, C. [CEA, Centre de Saclay, IRFU, Gif-sur-Yvette (France); Baba, H.; Doornenbal, P.; Otsu, H.; Uesaka, T. [RIKEN Nishina Center, Wako, Saitama (Japan)

    2014-01-15

    MINOS is a new apparatus dedicated to in-beam nuclear structure experiments with low-intensity exotic beams in inverse kinematics at intermediate energies above 150 MeV/nucleon. The device is composed of a thick liquid-hydrogen target coupled to a compact time projection chamber (TPC) serving as a vertex tracker. Either used for in-beam gamma spectroscopy of bound excited states or invariant-mass spectroscopy of unbound states, MINOS aims at improving the luminosity by a very significant factor compared to standard solid-target material experiments while improving experimental resolutions. (orig.)

  11. Fast Detection Allows Analysis of the Electronic Structure of Metalloprotein by X-ray Emission Spectroscopy at Room Temperature.

    Science.gov (United States)

    Davis, Katherine M; Mattern, Brian A; Pacold, Joseph I; Zakharova, Taisiya; Brewe, Dale; Kosheleva, Irina; Henning, Robert W; Graber, Timothy J; Heald, Steve M; Seidler, Gerald T; Pushkar, Yulia

    2012-07-19

    The paradigm of "detection-before-destruction" was tested for a metalloprotein complex exposed at room temperature to the high x-ray flux typical of third generation synchrotron sources. Following the progression of the x-ray induced damage by Mn Kβ x-ray emission spectroscopy, we demonstrated the feasibility of collecting room temperature data on the electronic structure of native Photosystem II, a trans-membrane metalloprotein complex containing a Mn(4)Ca cluster. The determined non-damaging observation timeframe (about 100 milliseconds using continuous monochromatic beam, deposited dose 1*10(7) photons/µm(2) or 1.3*10(4) Gy, and 66 microseconds in pulsed mode using pink beam, deposited dose 4*10(7) photons/µm(2) or 4.2*10(4) Gy) is sufficient for the analysis of this protein's electron dynamics and catalytic mechanism at room temperature. Reported time frames are expected to be representative for other metalloproteins. The described instrumentation, based on the short working distance dispersive spectrometer, and experimental methodology is broadly applicable to time-resolved x-ray emission analysis at synchrotron and x-ray free-electron laser light sources.

  12. Super-resolution microscopy based on fluorescence emission difference of cylindrical vector beams

    Science.gov (United States)

    Rong, Zihao; Kuang, Cuifang; Fang, Yue; Zhao, Guangyuan; Xu, Yingke; Liu, Xu

    2015-11-01

    We propose a novel fluorescence emission difference microscopy (FED) system based on focusing cylindrical vector beams. In conventional FED, a Gaussian beam and a 0-2π vortex phase plate are used to generate solid and hollow spots. We focus radially polarized and azimuthally polarized cylindrical vector beams to obtain an expanded solid spot and a shrunken hollow spot, taking advantage of the optical properties of cylindrical vector beams to improve the conventional FED performance. Our novel method enhances FED performance because the hollow spot size determines the FED resolution and an expanded solid spot effectively reduces negative side-lobe emergence during image processing. We demonstrate improved performance theoretically and experimentally using an in-house built FED. Our FED achieved resolution of less than λ/4 in test images of 100 nm nanoparticles, better than the confocal image resolution by a factor of approximately 1/3. We also discuss detailed simulation analyses and FED imaging of biological cells.

  13. Simulating systematic errors in X-ray absorption spectroscopy experiments: Sample and beam effects

    Energy Technology Data Exchange (ETDEWEB)

    Curis, Emmanuel [Laboratoire de Biomathematiques, Faculte de Pharmacie, Universite Rene, Descartes (Paris V)-4, Avenue de l' Observatoire, 75006 Paris (France)]. E-mail: emmanuel.curis@univ-paris5.fr; Osan, Janos [KFKI Atomic Energy Research Institute (AEKI)-P.O. Box 49, H-1525 Budapest (Hungary); Falkenberg, Gerald [Hamburger Synchrotronstrahlungslabor (HASYLAB), Deutsches Elektronen-Synchrotron (DESY)-Notkestrasse 85, 22607 Hamburg (Germany); Benazeth, Simone [Laboratoire de Biomathematiques, Faculte de Pharmacie, Universite Rene, Descartes (Paris V)-4, Avenue de l' Observatoire, 75006 Paris (France); Laboratoire d' Utilisation du Rayonnement Electromagnetique (LURE)-Ba-hat timent 209D, Campus d' Orsay, 91406 Orsay (France); Toeroek, Szabina [KFKI Atomic Energy Research Institute (AEKI)-P.O. Box 49, H-1525 Budapest (Hungary)

    2005-07-15

    The article presents an analytical model to simulate experimental imperfections in the realization of an X-ray absorption spectroscopy experiment, performed in transmission or fluorescence mode. Distinction is made between sources of systematic errors on a time-scale basis, to select the more appropriate model for their handling. For short time-scale, statistical models are the most suited. For large time-scale, the model is developed for sample and beam imperfections: mainly sample inhomogeneity, sample self-absorption, beam achromaticity. The ability of this model to reproduce the effects of these imperfections is exemplified, and the model is validated on real samples. Various potential application fields of the model are then presented.

  14. Annealing Behaviour of Helium Bubbles in Titanium Films by Thermal Desorption Spectroscopy and Positron Beam Analysis

    Institute of Scientific and Technical Information of China (English)

    LIU Chao-Zhuo; ZHOU Zhu-Ying; SHI Li-Qun; WANG Bao-Yi; HAO Xiao-Peng; ZHAO Guo-Qing

    2007-01-01

    @@ Helium-containing Ti films are prepared using magnetron sputtering in the helium-argon atmosphere. Isochronal annealing at different temperatures for an hour is employed to reveal the behaviour of helium bubble growth. Ion beam analysis is used to measure the retained helium content. Helium can release largely when annealing above 970 K. A thermal helium desorption spectroscopy system is constructed for assessment of the evolution of helium bubbles in the annealed samples by linear heating (0.4K/s) from room temperature to 1500K. Also, Doppler broadening measurements of positron annihilation radiation spectrum are performed by using changeable energy positron beam. Bubble coarsening evolves gradually below 680K, migration and coalescence of small bubbles dominates in the range of 680-970K, and the Ostwald ripening mechanism enlarges the bubbles with a massive release above 970K.

  15. In-beam γ-ray Spectroscopy of Level Structure in 134Ba

    Institute of Scientific and Technical Information of China (English)

    LuoPeng; LiuMinliang; LiuZhong; ZhangYuhu; ZhouXiaohong; GuoYingxiang; MaYingjun; Y.Sasaki; K.Yamada; H.Ohshima; S.Yokose; M.Ishizuka; T.Komatsubara; K.Furuno

    2003-01-01

    Excited states of 134Ba, populated via the heavy-ion induced 128Te(10B, 1p3n)134Ba reaction at 46 MeV beam energy, have been studied to medium and high spins by in-beam γ-ray spectroscopy techniques. The experiment was performed at the tandem accelerator laboratory in the University of Tsukuba, Japan. The target is an isotopically enriched 128Te metallic foil of 2.3mg/cm2 thickness with a 3mg/cm2 gold backing. Nine anti-Compton HPGe detectors were employed for the measurements of γ-γ-t coincidences. The level scheme of 134Ba, deduced from this study, was shown in Fig.1.

  16. Comb-assisted cavity ring-down spectroscopy of a buffer-gas-cooled molecular beam.

    Science.gov (United States)

    Santamaria, Luigi; Sarno, Valentina Di; Natale, Paolo De; Rosa, Maurizio De; Inguscio, Massimo; Mosca, Simona; Ricciardi, Iolanda; Calonico, Davide; Levi, Filippo; Maddaloni, Pasquale

    2016-06-22

    We demonstrate continuous-wave cavity ring-down spectroscopy of a partially hydrodynamic molecular beam emerging from a buffer-gas-cooling source. Specifically, the (ν1 + ν3) vibrational overtone band of acetylene (C2H2) around 1.5 μm is accessed using a narrow-linewidth diode laser stabilized against a GPS-disciplined rubidium clock via an optical frequency comb synthesizer. As an example, the absolute frequency of the R(1) component is measured with a fractional accuracy of ∼1 × 10(-9). Our approach represents the first step towards the extension of more sophisticated cavity-enhanced interrogation schemes, including saturated absorption cavity ring-down or two-photon excitation, to buffer-gas-cooled molecular beams.

  17. Proceeding of the workshop on gamma-ray spectroscopy utilizing heavy-ion, photon and RI beams

    Energy Technology Data Exchange (ETDEWEB)

    Oshima, Masumi; Sugita, Michiaki; Hayakawa, Takehito [eds.

    1998-03-01

    Three time since 1992, we have held the symposia entitled `Joint Spectroscopy Experiments Utilizing JAERI Tandem-Booster Accelerator` at the Tokai Research Establishment. In the symposia, we have mainly discussed the plans of experiments to be done in this joint program. The joint program started in 1994. Several experiments have been made since and some new results have already come up. This symposium `Gamma-ray Spectroscopy utilizing heavy-ion, Photon and RI beams` was held at Tokai Research Establishment of JAERI. Because this symposium is the first occasion after the program started, the first purpose of the symposium is to present and discuss the experimental results so far obtained using the JAERI Tandem-Booster. The second purpose of the symposium is to discuss new possibilities of gamma-ray spectroscopy using new resources such as RI-beam and Photon-beam. The participants from RIKEN, Tohoku University and JAERI Neutron Science Research Center presented the future plans of experiments with RI-beam at each facility. Compared with these nuclear beams, photon beam provides a completely new tool for the {gamma}-ray spectroscopy, which is achieved by inverse Compton scattering between high-energy electron and laser beams. The 23 of the presented papers are indexed individually. (J.P.N.)

  18. SPIDER beam dump as diagnostic of the particle beam

    Science.gov (United States)

    Zaupa, M.; Dalla Palma, M.; Sartori, E.; Brombin, M.; Pasqualotto, R.

    2016-11-01

    The beam power produced by the negative ion source for the production of ion of deuterium extracted from RF plasma is mainly absorbed by the beam dump component which has been designed also for measuring the temperatures on the dumping panels for beam diagnostics. A finite element code has been developed to characterize, by thermo-hydraulic analysis, the sensitivity of the beam dump to the different beam parameters. The results prove the capability of diagnosing the beam divergence and the horizontal misalignment, while the entity of the halo fraction appears hardly detectable without considering the other foreseen diagnostics like tomography and beam emission spectroscopy.

  19. Tomographic reconstruction of the beam emissivity profile in the negative ion source NIO1

    Science.gov (United States)

    Fonnesu, N.; Agostini, M.; Pasqualotto, R.; Serianni, G.; Veltri, P.

    2016-12-01

    A versatile negative hydrogen ion source named NIO1 of a moderate size (130 mA total extracted H- current, 9 apertures, 60 kV total acceleration) has been developed and installed at Consorzio RFX. It will allow great experimental flexibility, very beneficial for studying several important issues related to beam extraction, optics and performance optimization, in view of SPIDER and MITICA, the two full-scale experiments for the ITER neutral beam injector under construction at RFX. The main target of emission tomography applied to an ion beam is the reconstruction of the emissivity profile, from which the ion density distribution can be obtained. The measurement of the beam density profile and of its uniformity throughout the pulse duration with a non-invasive diagnostic, such as tomography, would represent an effective method for monitoring the ion source operation and for malfunction detection. The application of this diagnostic to the NIO1 beam will represent the experimental verification of the possibility to reconstruct a multi-beamlet profile, in the interest of the next tomography systems for SPIDER and MITICA. In this paper, a feasibility study of the tomographic diagnostic for NIO1 is presented. A tomography code based on algebraic reconstruction techniques has been developed for this purpose and the transport of the nine H- beamlets is simulated with a Monte Carlo particle tracking code from the ion source to the tomography plane, where the beam emissivity profile to be reconstructed is calculated. The reference emissivity profile is reconstructed by the tomography code considering different possible layouts of the detection system, in order to find the best compromise between the quality of reconstructions and the complexity of the diagnostic. Results show that a tomography system based on six linear CCD cameras should be capable of reconstructing the NIO1 emissivity profile with an rms error lower than 10%. How instrumental noise in the integrated

  20. In-beam measurement of the hydrogen hypernine splitting - towards antihydrogen spectroscopy

    CERN Document Server

    Diermaier, M.; Kolbinger, B.; Malbrunot, C.; Massiczek, O.; Sauerzopf, C.; Simon, M.C.; Zmeskal, J.; Widmann, E.

    2016-01-01

    Antihydrogen, the lightest atom consisting purely of antimatter, is an ideal laboratory to study the CPT symmetry by comparison to hydrogen. With respect to absolute precision, transitions within the ground-state hyperfine structure (GS-HFS) are most appealing by virtue of their small energy separation. ASACUSA proposed employing a beam of cold antihydrogen atoms in a Rabi-type experiment to determine the GS-HFS in a field-free region. Here we present a measurement of the zero-field hydrogen GS-HFS using the spectroscopy apparatus of ASACUSA's antihydrogen experiment. The measured value of $\

  1. In situ photoelectron spectroscopy of molecular-beam-epitaxy grown surfaces

    CERN Document Server

    Oshima, M; Okabayashi, J; Ono, K

    2003-01-01

    Two in situ high-resolution synchrotron radiation photoelectron spectroscopy (SRPES) systems combined with a molecular beam epitaxy (MBE) chamber for III-V compound semiconductors and a laser MBE chamber for strongly correlated oxide films, respectively, have been designed and fabricated to analyze intrinsic and surface/interface electronic structures of these unique materials. The importance of the in situ SRPES has been demonstrated by the results of 1) Si surface nanostructures, 2) GaAs surfaces/interfaces and nanostructures, 3) MnAs magnetic nanostructures, and 4) strongly-correlated La sub 1 sub - sub x Sr sub x MnO sub 3 surfaces/interfaces and superstructures.

  2. $\\beta$-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.

  3. Real-time reflectance-difference spectroscopy of GaAs molecular beam epitaxy homoepitaxial growth

    Directory of Open Access Journals (Sweden)

    A. Lastras-Martínez

    2014-03-01

    Full Text Available We report on real time-resolved Reflectance-difference (RD spectroscopy of GaAs(001 grown by molecular beam epitaxy, with a time-resolution of 500 ms per spectrum within the 2.3–4.0 eV photon energy range. Through the analysis of transient RD spectra we demonstrated that RD line shapes are comprised of two components with different physical origins and determined their evolution during growth. Such components were ascribed to the subsurface strain induced by surface reconstruction and to surface stoichiometry. Results reported in this paper render RD spectroscopy as a powerful tool for the study of fundamental processes during the epitaxial growth of zincblende semiconductors.

  4. 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.

  5. Detection of Bioaerosols using Single Particle Thermal Emission Spectroscopy

    Science.gov (United States)

    2013-03-01

    droplets was accomplished by using a peristaltic pump to inject a set flow-rate of liquid mineral oil into a heated hypodermic needle . Heated mineral...heated to temperatures in excess of a 100 °C. Prevailing theory suggests a strong link between thermal emission and absorption spectra for bulk...iv 1. Background 1 2. Theory 1 3. Experiment 5 4. Results 13 5. Conclusion 16 6. References 18 List of Symbols, Abbreviations, and Acronyms 20

  6. Emission Spectroscopy of the Interior of Optically Dense Post-Detonation Fireballs

    Science.gov (United States)

    2013-03-01

    TP-2013-011 Emission Spectroscopy of the Interior of Optically Dense Post-Detonation Fireballs Distribution A: Approved for public release...Detonation Fireballs 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 62102F 6. AUTHOR(S) W.K. Lewis1, C.G. Rumchik2, M.J...detonation fireballs that form as under- oxidized detonation products burn in the surrounding air are optically dense and the corresponding emission

  7. Real-time tissue differentiation based on optical emission spectroscopy for guided electrosurgical tumor resection

    OpenAIRE

    Spether, Dominik; Scharpf, Marcus; Hennenlotter, Jörg; Schwentner, Christian; Neugebauer, Alexander; Nüßle, Daniela; Fischer, Klaus; Zappe, Hans; Stenzl, Arnulf; Fend, Falko; Seifert, Andreas; Enderle, Markus

    2015-01-01

    Complete surgical removal of cancer tissue with effective preservation of healthy tissue is one of the most important challenges in modern oncology. We present a method for real-time, in situ differentiation of tissue based on optical emission spectroscopy (OES) performed during electrosurgery not requiring any biomarkers, additional light sources or other excitation processes. The analysis of the optical emission spectra, enables the differentiation of healthy and tumorous tissue. By using m...

  8. Nondestructive identification of ancient Chinese glasses by Raman and proton-induced X-ray emission spectroscopy

    Institute of Scientific and Technical Information of China (English)

    Hongxia Zhao; Huansheng Cheng; Qinghui Li; Fuxi Gan

    2011-01-01

    @@ Nondestructive Raman spectroscopy and external-beam proton-induced X-ray emission (PIXE) technique to analyze eight ancient glasses unearthed from the provinces of Henan, Hubei, and Jiangsu, which allowes for a good characterization of the glass matrix and chemical compositions, is carried out.The results indicate that all the eight glass samples could be typically divided into three systems: faience (sample No.SZWG-4), PbO-BaO-SiO2 (sample Nos.NYWKI-5-1, HNWKII-88, and HNWKII-84), and Na2O-CaO-SiO2 (sample Nos.HBWKI-16, HBWKI-17, HBWKI-18, and SZWG-1).Additional relationships between the Rarnan spectra and parameters, such as residues of raw materials and opacifying agent, are also discussed by respectively comparing them with similar glass samples excavated from other historical sites.%Nondestructive Raman spectroscopy and external-beam proton-induced X-ray emission (PIXE) technique to analyze eight ancient glasses unearthed from the provinces of Henan, Hubei, and Jiangsu, which allowes for a good characterization of the glass matrix and chemical compositions, is carried out.The results indicate that all the eight glass samples could be typically divided into three systems: faience (sample No.SZWG-4), PbO-BaO-SiO2 (sample Nos.NYWKⅠ-5-1, HNWKⅡ-88, and HNWKⅡ-84), and Na2OCaO-SiO2 (sample Nos.HBWKⅠ-16, HBWKⅠ-17, HBWKⅠ-18, and SZWG-1).Additional relationships between the Raman spectra and parameters, such as residues of raw materials and opacifying agent, are also discussed by respectively comparing them with similar glass samples excavated from other historical sites.

  9. A GAS TEMPERATURE PROFILE BY INFRARED EMISSION-ABSORPTION SPECTROSCOPY

    Science.gov (United States)

    Buchele, D. R.

    1994-01-01

    This computer program calculates the temperature profile of a flame or hot gas. Emphasis is on profiles found in jet engine or rocket engine exhaust streams containing water vapor or carbon dioxide as radiating gases. The temperature profile is assumed to be axisymmetric with a functional form controlled by two variable parameters. The parameters are calculated using measurements of gas radiation at two wavelengths in the infrared spectrum. Infrared emission and absorption measurements at two or more wavelengths provide a method of determining a gas temperature profile along a path through the gas by using a radiation source and receiver located outside the gas stream being measured. This permits simplified spectral scanning of a jet or rocket engine exhaust stream with the instrumentation outside the exhaust gas stream. This program provides an iterative-cyclic computation in which an initial assumed temperature profile is altered in shape until the computed emission and absorption agree, within specified limits, with the actual instrument measurements of emission and absorption. Temperature determination by experimental measurements of emission and absorption at two or more wavelengths is also provided by this program. Additionally, the program provides a technique for selecting the wavelengths to be used for determining the temperature profiles prior to the beginning of the experiment. By using this program feature, the experimenter has a higher probability of selecting wavelengths which will result in accurate temperature profile measurements. This program provides the user with a technique for determining whether this program will be sufficiently accurate for his particular application, as well as providing a means of finding the solution. The input to the program consists of four types of data: (1) computer program control constants, (2) measurements of gas radiance and transmittance at selected wavelengths, (3) tabulations from the literature of gas

  10. Feedback Control of Laser Welding Based on Frequency Analysis of Light Emissions and Adaptive Beam Shaping

    Science.gov (United States)

    Mrňa, L.; Šarbort, M.; Řeřucha, Š.; Jedlička, P.

    This paper presents a novel method for optimization and feedback control of laser welding process. It is based on frequency analysis of the light emitted during the process and adaptive shaping of the laser beam achieved by an active optical element. Experimentally observed correlations between the focal properties of the laser beam, the weld depth and the frequency characteristics of the light emissions, which form the basis of the method, are discussed in detail. The functionality and the high efficiency of the method are demonstrated for a variety of welding parameters settings usually used in industrial practice.

  11. Ground-based NIR emission spectroscopy of HD189733b

    CERN Document Server

    Waldmann, I P; Tinetti, G; Griffith, C A; Swain, M R; Deroo, P

    2011-01-01

    Spectroscopic observations of transiting exoplanets are providing an unprecedented view of the atmospheres of planets around nearby stars. As we learn more about the atmospheres of these remote bodies, we begin to build up a clearer picture of their composition and thermal structure. Here we investigate the case of K and L band emissions of the hot-Jupiter HD 189733b. Using the SpeX instrument on the NASA IRTF, we obtained three nights of secondary eclipse data using equivalent settings for all nights. Our sample includes one night previously presented by Swain et al. (2010) which allows for comparability of results. In this publication we present and discuss in detail a greatly improved data-reduction and analysis routine. This, in conjunction with more data, allows us to increase the spectral resolution of our planetary spectrum (R ~ 170-180), leading to a better identifiability of the features present. We confirm the existence of a strong emission at ~3.3 microns which is inconsistent with LTE simulations ...

  12. Detection of Delamination in Composite Beams Using Broadband Acoustic Emission Signatures

    Science.gov (United States)

    Okafor, A. C.; Chandrashekhara, K.; Jiang, Y. P.

    1996-01-01

    Delamination in composite structure may be caused by imperfections introduced during the manufacturing process or by impact loads by foreign objects during the operational life. There are some nondestructive evaluation methods to detect delamination in composite structures such as x-radiography, ultrasonic testing, and thermal/infrared inspection. These methods are expensive and hard to use for on line detection. Acoustic emission testing can monitor the material under test even under the presence of noise generated under load. It has been used extensively in proof-testing of fiberglass pressure vessels and beams. In the present work, experimental studies are conducted to investigate the use of broadband acoustic emission signatures to detect delaminations in composite beams. Glass/epoxy beam specimens with full width, prescribed delamination sizes of 2 inches and 4 inches are investigated. The prescribed delamination is produced by inserting Teflon film between laminae during the fabrication of composite laminate. The objectives of this research is to develop a method for predicting delamination size and location in laminated composite beams by combining smart materials concept and broadband AE analysis techniques. More specifically, a piezoceramic (PZT) patch is bonded on the surface of composite beams and used as a pulser. The piezoceramic patch simulates the AE wave source as a 3 cycles, 50KHz, burst sine wave. One broadband AE sensor is fixed near the PZT patch to measure the AE wave near the AE source. A second broadband AE sensor, which is used as a receiver, is scanned along the composite beams at 0.25 inch step to measure propagation of AE wave along the composite beams. The acquired AE waveform is digitized and processed. Signal strength, signal energy, cross-correlation of AE waveforms, and tracking of specific cycle of AE waveforms are used to detect delamination size and location.

  13. In-beam measurement of the hydrogen hypernine splitting - towards antihydrogen spectroscopy

    CERN Document Server

    Diermaier, Martin; The Asacusa AD-3 collaboration; Kolbinger, Bernadette; Malbrunot, Chloé; Massiczek, Oswald; Sauerzopf, Clemens; Simon, Martin Christian; Zmeskal, Johann; Widmann, Eberhard

    2016-01-01

    Antihydrogen, the lightest atom consisting purely of antimatter, is an ideal laboratory to study the CPT symmetry by comparison to hydrogen. With respect to absolute precision, transitions within the ground-state hyperfine structure (GS-HFS) are most appealing by virtue of their small energy separation. ASACUSA proposed employing a beam of cold antihydrogen atoms in a Rabi-type experiment to determine the GS-HFS in a field-free region. Here we present a measurement of the zero-field hydrogen GS-HFS using the spectroscopy apparatus of ASACUSA' s antihydrogen experiment. The measured value of nu_HF=1 420 405 748.4(3.4)(1.6) Hz with a relative precision of 2.7 × 10(−9) constitutes the most precise determination of this quantity in a beam and verifies the developed spectroscopy methods for the antihydrogen HFS experiment to the ppb level. Together with the recently presented observation of antihydrogen atoms 2.7 m downstream of the production region, the prerequisites for a measurement with antihydrogen are no...

  14. 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.

  15. Optical Emission Spectroscopy Investigation of a Surface Dielectric Barrier Discharge Plasma Aerodynamic Actuator

    Institute of Scientific and Technical Information of China (English)

    LI Ying-Hong; WU Yun; JIA Min; ZHOU Zhang-Wen; GUO Zhi-Gang; PU Yi-Kang

    2008-01-01

    The optical emission spectroscopy of a surface dielectric barrier discharge plasma aerodynamic actuator is investigated with different electrode configurations, applied voltages and driving frequencies. The rotational temperature of N2 (C3IIu) molecule is calculated according to its rotational emission band near 380.5 nm. The average electron energy of the discharge is evaluated by emission intensity ratio of first negative system to second positive system of N2. The rotational temperature is sensitive to the inner space of an electrode pair. The average electron energy shows insensitivity to the applied voltage, the driving frequency and the electrode configuration.

  16. APPLYING OPEN-PATH OPTICAL SPECTROSCOPY TO HEAVY-DUTY DIESEL EMISSIONS

    Science.gov (United States)

    Non-dispersive infrared absorption has been used to measure gaseous emissions for both stationary and mobile sources. Fourier transform infrared spectroscopy has been used for stationary sources as both extractive and open-path methods. We have applied the open-path method for bo...

  17. 2p3d Resonant X-ray emission spectroscopy of cobalt compounds

    NARCIS (Netherlands)

    van Schooneveld, M.M.

    2013-01-01

    This manuscript demonstrates that 2p3d resonant X-ray emission spectroscopy (RXES) yields unique information on the chemically relevant valence electrons of transition metal atoms or ions. Experimental data on cobalt compounds and several theories were used hand-in-hand. In chapter 1 2p3d RXES was s

  18. Single photon infrared emission spectroscopy: a study of IR emission from UV laser excited PAHs between 3 and 15 micrometers

    Science.gov (United States)

    Cook, D. J.; Schlemmer, S.; Balucani, N.; Wagner, D. R.; Harrison, J. A.; Steiner, B.; Saykally, R. J.

    1998-01-01

    Single-photon infrared emission spectroscopy (SPIRES) has been used to measure emission spectra from polycyclic aromatic hydrocarbons (PAHs). A supersonic free-jet expansion has been used to provide emission spectra of rotationally cold and vibrationally excited naphthalene and benzene. Under these conditions, the observed width of the 3.3-micrometers (C-H stretch) band resembles the bandwidths observed in experiments in which emission is observed from naphthalene with higher rotational energy. To obtain complete coverage of IR wavelengths relevant to the unidentified infrared bands (UIRs), UV laser-induced desorption was used to generate gas-phase highly excited PAHs. Lorentzian band shapes were convoluted with the monochromator-slit function in order to determine the widths of PAH emission bands under astrophysically relevant conditions. Bandwidths were also extracted from bands consisting of multiple normal modes blended together. These parameters are grouped according to the functional groups mostly involved in the vibration, and mean bandwidths are obtained. These bandwidths are larger than the widths of the corresponding UIR bands. However, when the comparison is limited to the largest PAHs studied, the bandwidths are slightly smaller than the corresponding UIR bands. These parameters can be used to model emission spectra from PAH cations and cations of larger PAHs, which are better candidate carriers of the UIRs.

  19. Relativistic Pair Beams from TeV Blazars: A Source of Reprocessed GeV Emission rather than IGM Heating

    CERN Document Server

    Sironi, Lorenzo

    2013-01-01

    The interaction of TeV photons from blazars with the extragalactic background light produces a relativistic beam of electron-positron pairs streaming through the intergalactic medium (IGM). The fate of the beam energy is uncertain. By means of two- and three-dimensional particle-in-cell simulations, we study the non-linear evolution of dilute ultra-relativistic pair beams propagating through the IGM. We explore a wide range of beam Lorentz factors gamma_b>>1 and beam-to-plasma density ratios alpha 0.2 (as typically expected for blazar-induced beams), the fraction of beam energy deposited into the IGM is much smaller than ~10%. It follows that at least ~90% of the beam energy is still available to power the GeV emission produced by inverse Compton up-scattering of the Cosmic Microwave Background by the beam pairs.

  20. The influence of magnetic fields on absorption and emission spectroscopy

    CERN Document Server

    Zhang, Heshou; Richter, Philipp

    2016-01-01

    Spectroscopic observations play essential roles in astrophysics. They are crucial for determining important physical parameters, providing information about the composition of various objects in the universe, as well as depicting motions in the universe. However, spectroscopic studies often do not consider the influence of magnetic fields. In this paper, we explore the influence of magnetic fields on the spectroscopic observations arising from Ground State Alignment (GSA). Synthetic spectra are generated to show the measurable changes of the spectra due to GSA. The influences of atomic alignment on absorption from DLAs, emission from H\\,{\\sc ii} Regions, submillimeter fine-structure lines from star forming regions are presented as examples to illustrate the effect in diffuse gas. Furthermore, we demonstrate the influence of atomic alignment on physical parameters derived from spectral line ratios, such as the alpha-to-iron ratio([X/Fe]), interstellar temperature, and ionization rate. Results in our paper show...

  1. Field-emission spectroscopy of beryllium atoms adsorbed on tungsten

    Energy Technology Data Exchange (ETDEWEB)

    Czyzewski, J.J.; Grzesiak, W.; Krajniak, J. (Politechnika Wroclawska (Poland))

    1981-01-01

    Field emission energy distributions (FEED) have been measured for the beryllium-tungsten (023) adsorption system over the 78-450 K temperature range. A temperature dependence of the normalized half-width, ..delta../d, of FEED peaks changed significantly due to beryllium adsorption; and the curve, ..delta../d vs p, for the Be/W adsorption system was identical in character to the calculated curve based on the free electron model in contrast to the curve for the clean tungsten surface. In the last part of this paper Gadzuk's theory of the resonance-tunneling effect is applied to the beryllium atom on tungsten. Experimental and theoretical curves of the enhancement factor as a function of energy have been discussed.

  2. Enhanced coherent emission of terahertz radiation by energy-phase correlation in a bunched electron beam.

    Science.gov (United States)

    Doria, A; Gallerano, G P; Giovenale, E; Messina, G; Spassovsky, I

    2004-12-31

    We report the first observation of enhanced coherent emission of terahertz radiation in a compact free electron laser. A radio-frequency (rf) modulated electron beam is passed through a magnetic undulator emitting coherent radiation at harmonics of the rf with a phase which depends on the electron drift velocity. A proper correlation between the energy and phase distributions of the electrons in the bunch has been exploited to lock in phase the radiated field, resulting in over 1 order of magnitude enhancement of the coherent emission.

  3. Second harmonic electromagnetic emission of a turbulent magnetized plasma driven by a powerful electron beam

    CERN Document Server

    Timofeev, I V

    2012-01-01

    The power of second harmonic electromagnetic emission is calculated for the case when strong plasma turbulence is excited by a powerful electron beam in a magnetized plasma. It is shown that the simple analytical model of strong plasma turbulence with the assumption of a constant pump power is able to explain experimentally observed bursts of electromagnetic radiation as a consequence of separate collapse events. It is also found that the electromagnetic emission power calculated for three-wave interaction processes occurring in the long-wavelength part of turbulent spectrum is in order-of-magnitude agreement with experimental results.

  4. Spectroscopy of bright quasars: emission lines and internal extinction

    CERN Document Server

    Bachev, R; Semkov, E; Mihov, B

    2008-01-01

    The main purpose of this work is to improve the existing knowledge about the most powerful engines in the Universe - quasars. Although a lot is already known, we still have only a vague idea how these engines work exactly, why they behave as they do, and what the relation is between their evolution and the evolution of their harboring galaxy. Methods we used are based on optical spectroscopy of visually bright quasars, many of which have recently been discovered as X-ray sources, but eventually missed in color-selected surveys. The spectra typically cover the 4200-7000 AA region, allowing measurements of the characteristics of the hydrogen lines, the FeII contribution, and other lines of interest. We present accurate redshift estimates and Seyfert type classification of the objects. We also show that the contribution of the host galaxy to the optical continuum is non-negligible in many cases, as is the intrinsic AGN absorption. Consequences of not correcting for those factors when estimating different quasar ...

  5. Secondary emission monitor for keV ion and antiproton beams

    CERN Document Server

    Sosa, Alejandro; Bravin, Enrico; Harasimowciz, Janusz; Welsch, C P

    2013-01-01

    Beam profile monitoring of low intensity keV ion and antiproton beams remains a challenging task. A Sec- ondary electron Emission Monitor (SEM) has been de- signed to measure profiles of beams with intensities below 107 and energies as low as 20 keV. The monitor is based on a two stage microchannel plate (MCP) and a phosphor screen facing a CCD camera. Its modular design allows two different operational setups. In this contribution we present the design of a prototype and discuss results from measurements with antiprotons at the AEgIS experiment at CERN. This is then used for a characterization of the monitor with regard to its possible future use at different facilities.

  6. Experimental validation of ultra-thin metalenses for N-beam emissions based on transformation optics

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Kuang, E-mail: zhangkuang@hit.edu.cn [Department of Microwave Engineering, Harbin Institute of Technology, Harbin 150001 (China); State Key Laboratory of Millimeter Waves, Nanjing 210096 (China); Ding, Xumin; Meng, Fanrong; Wu, Qun [Department of Microwave Engineering, Harbin Institute of Technology, Harbin 150001 (China); Wo, Deliang [Shang Hai Electro-Mechanical Engineering Institute, Shanghai 201109 (China)

    2016-02-01

    A general design of metalenses for N-beam emissions is proposed based on transformation optics. A linear mapping function is adopted to achieve the homogeneous characterization of the transforming medium, which is therefore easy to be achieved compared with previous designs limited by inhomogeneity based on transformation optics. To verify the theoretical design, a four-beam antenna constructed with ultrathin, homogenous, and uniaxial anisotropic metalens is designed, fabricated, and measured. It is shown that the realized gain of the four-beam antenna is increased by 6 dB compared with the single dipole source, while working frequency and relative bandwidth are kept unchanged. The measured far-field pattern verifies theoretical design procedure.

  7. Beam profile measurement of ES-200 using secondary electron emission monitor

    Directory of Open Access Journals (Sweden)

    E Ebrahimi Basabi

    2015-09-01

    Full Text Available Up to now, different designs have been introduced for measurement beam profile accelerators. Secondary electron emission monitors (SEM are one of these devices which have been used for this purpose. In this work, a SEM has been constructed to measure beam profile of ES-200 accelerator, a proton electrostatic accelerator which is installed at SBU. Profile grid for both planes designed with 16 wires which are insulated relative to each other. The particles with maximum energy of 200 keV and maximum current of 400 μA are stopped in copper wires. Each of the wires has an individual current-to-voltage amplifier. With a multiplexer, the analogue values are transported to an ADC. The ADCs are read out by a microcontroller and finally profile of beam shows by a user interface program

  8. Rapid evaluation of ion thruster lifetime using optical emission spectroscopy

    Science.gov (United States)

    Rock, B. A.; Parsons, M. L.; Mantenieks, M. A.

    1985-01-01

    A major life-limiting phenomenon of electric thrusters is the sputter erosion of discharge chamber components. Thrusters for space propulsion are required to operate for extended periods of time, usually in excess of 10,000 hr. Lengthy and very costly life-tests in high-vacuum facilities have been required in the past to determine the erosion rates of thruster components. Alternative methods for determining erosion rates which can be performed in relatively short periods of time at considerably lower costs are studied. An attempt to relate optical emission intensity from an ion bombarded surface (screen grid) to the sputtering rate of that surface is made. The model used a kinetic steady-state (KSS) approach, balancing the rates of population and depopulation of ten low-lying excited states of the sputtered molybdenum atom (MoI) with those of the ground state to relate the spectral intensities of the various transitions of the MoI to the population densities. Once this is accomplished, the population density can be related to the sputting rate of the target. Radiative and collisional modes of excitation and decay are considered. Since actual data has not been published for MoI excitation rate and decay constants, semiempirical equations are used. The calculated sputtering rate and intensity is compared to the measured intensity and sputtering rates of the 8 and 30 cm ion thrusters.

  9. Absorption spectroscopy characterization measurements of a laser-produced Na atomic beam

    Energy Technology Data Exchange (ETDEWEB)

    Ching, C.H.; Bailey, J.E.; Lake, P.W.; Filuk, A.B.; Adams, R.G.; McKenney, J.

    1996-06-01

    This work describes a pulsed Na atomic beam source developed for spectroscopic diagnosis of a high-power ion diode on the Particle Beam Fusion Accelerator II. The goal is to produce a {approximately} 10{sup 12}-cm{sup {minus}3}-density Na atomic beam that can be injected into the diode acceleration gap to measure electric and magnetic fields from the Stark and Zeeman effects through laser-induced-fluorescence or absorption spectroscopy. A {approximately} 10 ns fwhm, 1.06 {micro}m, 0.6 J/cm{sup 2} laser incident through a glass slide heats a Na-bearing thin film, creating a plasma that generates a sodium vapor plume. A {approximately} 1 {micro}sec fwhm dye laser beam tuned to 5,890 {angstrom} is used for absorption measurement of the Na I resonant doublet by viewing parallel to the film surface. The dye laser light is coupled through a fiber to a spectrograph with a time-integrated CCD camera. A two-dimensional mapping of the Na vapor density is obtained through absorption measurements at different spatial locations. Time-of-flight and Doppler broadening of the absorption with {approximately} 0.1 {angstrom} spectral resolution indicate that the Na neutral vapor temperature is about 0.5 to 2 eV. Laser-induced-fluorescence from {approximately} 1 {times} 10{sup 12}-cm{sup {minus}3} Na I 3s-3p lines observed with a streaked spectrograph provides a signal level sufficient for {approximately} 0.06 {angstrom} wavelength shift measurements in a mock-up of an ion diode experiment.

  10. Identification of microcrystalline rocks using thermal emission spectroscopy

    Science.gov (United States)

    Hardgrove, C. J.; Rogers, D.; Glotch, T. D.; Arnold, J. A.

    2015-12-01

    High-silica deposits on Mars have been discovered from orbit (Holden Crater, Mawrth Vallis) and from landed surface missions to both Gusev Crater (Spirit) and Gale Crater (Curiosity). The character of these silica deposits can be used to understand both the depositional environment (i.e. fumarole vs. sinter) and/or diagenetic process. Initial work has shown that, in the case of opaline silica, there are differences in spectral shape that may be related to surface textural features imparted during formation or post-depositional alteration. Due to the increasing importance of understanding microcrystalline deposits on Mars, here, we study the effects of crystal size and surface roughness on thermal infrared emission spectra of micro- and macro-crystalline quartz. The spectra of chert and macro-crystalline quartz have significant differences in both spectral contrast, and in the rounded doublet between ~1000-1250 cm-1, which can shift and appear less rounded in microcrystalline samples. We find that microcrystalline minerals exhibit naturally rough surfaces compared to their macrocrystalline counterparts at the 10 micron scale; and that this roughness causes distinct spectral differences within the Reststrahlen bands. We find that surface roughness, if rough on the scale of the wavelengths where the wavelength-dependent absorption coefficient (k) is large, can cause not only decreased spectral contrast, but also substantial changes in spectral shape. The spectral shape differences are small enough that the composition of the material is still recognizable, but large enough such that a roughness effect could be detected. We find that my studying the thermal infrared spectral character of the sample, it may be possible to make general inferences about microcrystallinity, and thus aid in the potential reconstruction of sedimentary rock diagenesis.

  11. X-ray photo-emission and energy dispersive spectroscopy of HA coated titanium

    Energy Technology Data Exchange (ETDEWEB)

    Drummond, J.L.; Steinberg, A.D. [Univ. of Illinois, Chicago, IL (United States); Krauss, A.R. [Argonne National Lab., IL (United States)] [and others

    1997-08-01

    The purpose of this study was to determine the chemical composition changes of hydroxyapatite (HA) coated titanium using surface analysis (x-ray photo-emission) and bulk analysis (energy dispersive spectroscopy). The specimens examined were controls, 30 minutes and 3 hours aged specimens in distilled water or 0.2M sodium phosphate buffer (pH 7.2) at room temperature. Each x-ray photo-emission cycle consisted of 3 scans followed by argon sputtering for 10 minutes for a total of usually 20 cycles, corresponding to a sampling depth of {approximately} 1500 {angstrom}. The energy dispersive spectroscopy analysis was on a 110 by 90 {mu}m area for 500 sec. Scanning electron microscopy examination showed crystal formation (3P{sub 2}O{sub 5}*2CAO*?H{sub 2}O by energy dispersive spectroscopy analysis) on the HA coating for the specimens aged in sodium phosphate buffer. The x-ray photo-emission results indicated the oxidation effect of water on the titanium (as TiO{sub 2}) and the effect of the buffer to increase the surface concentration of phosphorous. No differences in the chemical composition were observed by energy dispersive spectroscopy analysis. The crystal growth was only observed for the sodium phosphate buffer specimens and only on the HA surface.

  12. A Model of Jupiter's Decametric Radio Emissions as a Searchlight Beam

    Science.gov (United States)

    Imai, K.; Garcia, L.; Reyes, F.; Imai, M.; Thieman, J. R.

    It has long been recognized that there is a marked long-term periodic variation in Jupiter's integrated radio occurrence probability. The period of the variation is on the order of a decade. Carr et al. [1970] showed that such variations are closely correlated with Jovicentric declination of the Earth (DE). The range of the smoothed variation of DE is from approximately +3.3 to -3.3 degrees. This DE effect was extensively studied and confirmed by Garcia [1996]. It shows that the occurrence probability of the non-Io-A source is clearly controlled by DE at 18, 20, and 22 MHz during the 1957-1994 apparitions. We propose a new model to explain the DE effect. This new model shows that the beam structure of Jupiter radio emissions, which has been thought of like a hollow-cone, has a narrow beam like a searchlight, which can be explained by assuming that the three dimensional shape of the radio source expands along the line of the magnetic field. If we consider the sizes of the radio coherent region are 1000 m along Jupiter's magnetic field line and 200 m along the latitudinal direction, the equivalent beam pattern is 1 degree wide along Jupiter's magnetic field line and 5 degrees in latitude. As the searchlight beam is fixed with Jupiter's magnetic field, the pure geometrical effect of DE can be explained by this searchlight beam model.

  13. Application of filter method for detection of secondary electron emission in the auto-oscillating mode of beam plasma discharge

    Science.gov (United States)

    Balovnev, A. V.; Vizgalov, I. V.; Salahutdinov, G. H.

    2016-01-01

    In this paper we studied the non-self mode of the auto-oscillation secondary- emission discharge (ASED) in a longitudinal magnetic field with autonomous electron gun to ignite the primary beam-plasma discharge (PPD).

  14. Excitation emission and time-resolved fluorescence spectroscopy of selected varnishes used in historical musical instruments.

    Science.gov (United States)

    Nevin, Austin; Echard, Jean-Philippe; Thoury, Mathieu; Comelli, Daniela; Valentini, Gianluca; Cubeddu, Rinaldo

    2009-11-15

    The analysis of various varnishes from different origins, which are commonly found on historical musical instruments was carried out for the first time with both fluorescence excitation emission spectroscopy and laser-induced time-resolved fluorescence spectroscopy. Samples studied include varnishes prepared using shellac, and selected diterpenoid and triterpenoid resins from plants, and mixtures of these materials. Fluorescence excitation emission spectra have been collected from films of naturally aged varnishes. In parallel, time-resolved fluorescence spectroscopy of varnishes provides means for discriminating between short- (less than 2.0 ns) and long-lived (greater than 7.5 ns) fluorescence emissions in each of these complex materials. Results suggest that complementary use of the two non destructive techniques allows a better understanding of the main fluorophores responsible for the emission in shellac, and further provides means for distinguishing the main classes of other varnishes based on differences in fluorescence lifetime behaviour. Spectrofluorimetric data and time resolved spectra presented here may form the basis for the interpretation of results from future in situ fluorescence examination and time resolved fluorescence imaging of varnished musical instruments.

  15. Higher harmonic emission by a relativistic electron beam in a longitudinal magnetic wiggler

    Science.gov (United States)

    Davidson, Ronald C.; McMullin, Wayne A.

    1982-10-01

    The classical limit of the Einstein-coefficient method is used in the low-gain regime to calculate the stimulated emission from a tenuous relativistic electron beam propagating in the combined solenoidal and longitudinal wiggler fields (B0+δB k0z)e^z produced near the axis of a multiple-mirror (undulator) field configuration. Emission is found to occur at all harmonics of the wiggler wave number k0 with Doppler upshifted output frequency given by ω=(lk0Vb+ωcb)(1+Vbc)γ2b(1+γ2bV2⊥c2), where l>=1. The emission is compared to the low-gain cyclotron maser with δB=0 and to the low-gain free-electron laser (operating at higher harmonics) utilizing a transverse linearly polarized wiggler field.

  16. Measuring the Density of a Molecular Cluster Injector via Visible Emission from an Electron Beam

    Energy Technology Data Exchange (ETDEWEB)

    Lundberg, D. P.; Kaita, R.; Majeski, R. M.; Stotler, D. P.

    2010-06-28

    A method to measure the density distribution of a dense hydrogen gas jet is pre- sented. A Mach 5.5 nozzle is cooled to 80K to form a flow capable of molecular cluster formation. A 250V, 10mA electron beam collides with the jet and produces Hα emission that is viewed by a fast camera. The high density of the jet, several 1016cm-3, results in substantial electron depletion, which attenuates the Hα emission. The attenuated emission measurement, combined with a simplified electron-molecule collision model, allows us to determine the molecular density profile via a simple iterative calculation.

  17. Intense terahertz emission from molecular beam epitaxy-grown GaAs/GaSb(001)

    Energy Technology Data Exchange (ETDEWEB)

    Sadia, Cyril P.; Laganapan, Aleena Maria; Agatha Tumanguil, Mae; Estacio, Elmer; Somintac, Armando; Salvador, Arnel [National Institute of Physics, University of the Philippines Diliman, Quezon City 1101 (Philippines); Que, Christopher T. [Physics Department, De La Salle University, 2401 Taft Avenue, Manila 1004 (Philippines); Yamamoto, Kohji; Tani, Masahiko [Research Center for Development of Far-Infrared Region, University of Fukui, Fukui 910-8507 (Japan)

    2012-12-15

    Intense terahertz (THz) electromagnetic wave emission was observed in undoped GaAs thin films deposited on (100) n-GaSb substrates via molecular beam epitaxy. GaAs/n-GaSb heterostructures were found to be viable THz sources having signal amplitude 75% that of bulk p-InAs. The GaAs films were grown by interruption method during the growth initiation and using various metamorphic buffer layers. Reciprocal space maps revealed that the GaAs epilayers are tensile relaxed. Defects at the i-GaAs/n-GaSb interface were confirmed by scanning electron microscope images. Band calculations were performed to infer the depletion region and electric field at the i-GaAs/n-GaSb and the air-GaAs interfaces. However, the resulting band calculations were found to be insufficient to explain the THz emission. The enhanced THz emission is currently attributed to a piezoelectric field induced by incoherent strain and defects.

  18. In beam {gamma}-ray spectroscopy of the odd-odd nucleus {sup 144}Tb

    Energy Technology Data Exchange (ETDEWEB)

    Sferrazza, M. [Padua Univ. (Italy). Dipt. di Fisica]|[Istituto Nazionale di Fisica Nucleare, Padua (Italy)]|[Cambridge Univ. (United Kingdom). Cavendish Lab.; Cardona, M.A. [Istituto Nazionale di Fisica Nucleare, Legnaro (Italy). Lab. Nazionali di Legnaro; Bazzacco, D. [Padua Univ. (Italy). Dipt. di Fisica]|[Istituto Nazionale di Fisica Nucleare, Padua (Italy); Lunardi, S. [Padua Univ. (Italy). Dipt. di Fisica]|[Istituto Nazionale di Fisica Nucleare, Padua (Italy); Maglione, E. [Padua Univ. (Italy). Dipt. di Fisica]|[Istituto Nazionale di Fisica Nucleare, Padua (Italy); De Angelis, G. [Istituto Nazionale di Fisica Nucleare, Legnaro (Italy). Lab. Nazionali di Legnaro

    1996-03-01

    The level scheme of the N=79 nucleus {sup 144}Tb was investigated via in beam {gamma}-ray spectroscopy using the {sup 112}Sn({sup 35}Cl,n2p), {sup 116}Sn({sup 32}S,3np) and {sup 89}Y({sup 58}Ni,2np) reactions. States up to I{approx}20 and E{sub x}{approx}5 MeV were established above the 6{sup -} {beta}{sup +} decaying isomer. Two new isomers with half-life of 0.67(6) {mu}s and 2.8(3) {mu}s were identified. The level scheme of {sup 144}Tb is interpreted in the framework of the spherical shell model with a few valence nucleons outside the {sup 146}Gd core. (orig.)

  19. 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.

  20. Ion rotational velocity of a field-reversed configuration plasma measured by neutral beam probe spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Ito, Y.; Tanjyo, M.; Ohi, S.; Goto, S.; Ishimura, T.

    1987-01-01

    The ion rotational angular velocity ..cap omega.. and the ion temperature T/sub i/ of a translated field-reversed configuration (FRC) plasma are measured using neutral beam probe spectroscopy. The value of ..cap omega.. is --(1.0--1.2) x ..cap omega..* at the onset time of the n = 2 rotational instability, where ..cap omega..* is the ion diamagnetic frequency for a rigid-rotor equilibrium. The ion rotational direction is the same as the ion diamagnetic direction. The value of ..cap omega.. is smaller than the angular frequency ..omega../sub re/ of the n = 2 instability, which can yield experimental evidence of the ion kinetic effects on the n = 2 instability in the FRC plasma. When the octupole field is applied to the plasma in order to suppress the n = 2 deformation, ..cap omega.. is slightly reduced. The ion temperature T/sub i/ is --70 eV at the onset time of the n = 2 instability.

  1. 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.

  2. The applications of in situ electron energy loss spectroscopy to the study of electron beam nanofabrication.

    Science.gov (United States)

    Chen, Shiahn J; Howitt, David G; Gierhart, Brian C; Smith, Rosemary L; Collins, Scott D

    2009-06-01

    An in situ electron energy loss spectroscopy (EELS) technique has been developed to investigate the dynamic processes associated with electron-beam nanofabrication on thin membranes. In this article, practical applications germane to e-beam nanofabrication are illustrated with a case study of the drilling of nanometer-sized pores in silicon nitride membranes. This technique involves successive acquisitions of the plasmon-loss and the core-level ionization-loss spectra in real time, both of which provide the information regarding the hole-drilling kinetics, including two respective rates for total mass loss, individual nitrogen and silicon element depletion, and the change of the atomic bonding environment. In addition, the in situ EELS also provides an alternative method for endpoint detection with a potentially higher time resolution than by imaging. On the basis of the time evolution of in situ EELS spectra, a qualitative working model combining knock-on sputtering, irradiation-induced mass transport, and phase separation can be proposed.

  3. Hole emission from Ge/Si quantum dots studied by time-resolved capacitance spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Kapteyn, C.M.A.; Lion, M.; Heitz, R.; Bimberg, D. [Technische Univ. Berlin (Germany). Inst. fuer Festkoerperphysik; Miesner, C.; Asperger, T.; Brunner, K.; Abstreiter, G. [Technische Univ. Muenchen, Garching (Germany). Walter-Schottky-Inst. fuer Physikalische Grundlagen der Halbleiterelektronik

    2001-03-01

    Emission of holes from self-organized Ge quantum dots (QDs) embedded in Si Schottky diodes is studied by time-resolved capacitance spectroscopy (DLTS). The DLTS signal is rather broad and depends strongly on the filling and detection bias conditions. The observed dependence is interpreted in terms of carrier emission from many-hole states of the QDs. The activation energies obtained from the DLTS measurements are a function of the amount of stored charge and the position of the Fermi level in the QDs. (orig.)

  4. Determination of heavy metals in solid emission and immission samples using atomic absorption spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Fara, M.; Novak, F. [EGU Prague, PLC, Bichovice, Prague (Czechoslovakia)

    1995-12-01

    Both flame and electrothermal methods of atomic absorption spectroscopy (AAS) have been applied to the determination of Al, As, Be, Ca, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, TI, Se, V and Zn in emission and emission (deposition) samples decomposed in open PTFE test-tubes by individual fuming-off hydrofluoric, perchloroic and nitric acid. An alternative hydride technique was also used for As and Se determination and Hg was determined using a self-contained AAS analyzer. A graphite platform proved good to overcome non-spectral interferences in AAS-ETA. Methods developed were verified by reference materials (inc. NBS 1633a).

  5. Electrochemical impedance spectroscopy on nanostructured carbon electrodes grown by supersonic cluster beam deposition

    Energy Technology Data Exchange (ETDEWEB)

    Bettini, Luca Giacomo; Bardizza, Giorgio; Podesta, Alessandro; Milani, Paolo; Piseri, Paolo, E-mail: piseri@mi.infn.it [Universita degli Studi di Milano, Dipartimento di Fisica and CIMaINa (Italy)

    2013-02-15

    Nanostructured porous films of carbon with density of about 0.5 g/cm{sup 3} and 200 nm thickness were deposited at room temperature by supersonic cluster beam deposition (SCBD) from carbon clusters formed in the gas phase. Carbon film surface topography, determined by atomic force microscopy, reveals a surface roughness of 16 nm and a granular morphology arising from the low kinetic energy ballistic deposition regime. The material is characterized by a highly disordered carbon structure with predominant sp2 hybridization as evidenced by Raman spectroscopy. The interface properties of nanostructured carbon electrodes were investigated by cyclic voltammetry and electrochemical impedance spectroscopy employing KOH 1 M solution as aqueous electrolyte. An increase of the double layer capacitance is observed when the electrodes are heat treated in air or when a nanostructured nickel layer deposited by SCBD on top of a sputter deposited film of the same metal is employed as a current collector instead of a plain metallic film. This enhancement is consistent with an improved charge injection in the active material and is ascribed to the modification of the electrical contact at the interface between the carbon and the metal current collector. Specific capacitance values up to 120 F/g have been measured for the electrodes with nanostructured metal/carbon interface.

  6. GROUND-BASED NEAR-INFRARED EMISSION SPECTROSCOPY OF HD 189733B

    Energy Technology Data Exchange (ETDEWEB)

    Waldmann, I. P.; Tinetti, G. [Department of Physics and Astronomy, University College London, Gower Street, WC1E 6BT (United Kingdom); Drossart, P. [LESIA, Observatoire de Paris, CNRS, Universit Pierre et Marie Curie, Universit Paris-Diderot. 5 place Jules Janssen, 92195 Meudon (France); Swain, M. R.; Deroo, P. [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109-8099 (United States); Griffith, C. A., E-mail: ingo@star.ucl.ac.uk [Department of Planetary Sciences, University of Arizona, 1629 E. University Blvd, Tucson, AZ 85721 (United States)

    2012-01-01

    We investigate the K- and L-band dayside emission of the hot-Jupiter HD 189733b with three nights of secondary eclipse data obtained with the SpeX instrument on the NASA Infrared Telescope Facility. The observations for each of these three nights use equivalent instrument settings and the data from one of the nights have previously been reported by Swain et al. We describe an improved data analysis method that, in conjunction with the multi-night data set, allows increased spectral resolution (R {approx} 175) leading to high-confidence identification of spectral features. We confirm the previously reported strong emission at {approx}3.3 {mu}m and, by assuming a 5% vibrational temperature excess for methane, we show that non-LTE emission from the methane {nu}{sub 3} branch is a physically plausible source of this emission. We consider two possible energy sources that could power non-LTE emission and additional modeling is needed to obtain a detailed understanding of the physics of the emission mechanism. The validity of the data analysis method and the presence of strong 3.3 {mu}m emission are independently confirmed by simultaneous, long-slit, L-band spectroscopy of HD 189733b and a comparison star.

  7. Detection of bond failure in the anchorage zone of reinforced concrete beams via acoustic emission monitoring

    Science.gov (United States)

    Abouhussien, Ahmed A.; Hassan, Assem A. A.

    2016-07-01

    In this study, acoustic emission (AE) monitoring was utilised to identify the onset of bond failure in reinforced concrete beams. Beam anchorage specimens were designed and tested to fail in bond in the anchorage zone. The specimens included four 250 × 250 × 1500 mm beams with four variable bonded lengths (100, 200, 300, and 400 mm). Meanwhile, an additional 250 × 250 × 2440 mm beam, with 200 mm bonded length, was tested to investigate the influence of sensor location on the identification of bond damage. All beams were tested under four-point loading setup and continuously monitored using three distributed AE sensors. These attached sensors were exploited to record AE signals resulting from both cracking and bond deterioration until failure. The variations in the number of AE hits and cumulative signal strength (CSS) versus test time were evaluated to achieve early detection of crack growth and bar slippage. In addition, AE intensity analysis was performed on signal strength of collected AE signals to develop two additional parameters: historic index (H (t)) and severity (S r). The analysis of these AE parameters enabled an early detection of both first cracks (at almost the mid-span of the beam) and bar slip in either of the anchorage zones at the beams’ end before their visual observation, regardless of sensor location. The results also demonstrated a clear correlation between the damage level in terms of crack development/measured free end bar slip and AE parameters (number of hits, CSS, H(t), and S r).

  8. Characterization by acoustic emission and electrochemical impedance spectroscopy of the cathodic disbonding of Zn coating

    Energy Technology Data Exchange (ETDEWEB)

    Amami, Souhail [Universite de Technologie de Compiegne, Departement de Genie Mecanique, Laboratoire Roberval, UMR 6066 du CNRS, B.P. 20529, 60206 Compiegne Cedex (France)], E-mail: souhail.amami@utc.fr; Lemaitre, Christian; Laksimi, Abdelouahed; Benmedakhene, Salim [Universite de Technologie de Compiegne, Departement de Genie Mecanique, Laboratoire Roberval, UMR 6066 du CNRS, B.P. 20529, 60206 Compiegne Cedex (France)

    2010-05-15

    Galvanized steel has been tested in a synthetic sea water solution under different cathodic overprotection conditions. The generated hydrogen flux caused the damage of the metal-zinc interface and led to a progressive coating detachment. Scanning electron microscopy, electrochemical impedance spectroscopy and acoustic emission technique were used to characterize the damage chronology under different cathodic potentials. A damage mechanism was proposed and the acoustic signature related to the coating degradation was statistically identified using clustering techniques.

  9. Characterizing a multi-MeV e-beam induced plasma through visible spectroscopy and imaging

    Science.gov (United States)

    D'Almeida, Thierry; Ribiere, Maxime; Maisonny, Rémi; Ritter, Sandra; Plouhinec, Damien; Auriel, Gérard

    2016-10-01

    High energy electrons interaction and propagation mechanisms in solid targets have a broad range of applications in high energy density physics. The latter include fast ignition for inertial fusion research, production of ultra-high mechanical stress levels, plasma interactions with e-beam particles in electron diodes, radiative hydrodynamic models...This paper presents the results from recent experiments conducted on the multi-MeV generator ASTERIX operated at CEA-Gramat. This high flux density electron beam was launched from an aluminum cathode onto an aluminum-tantalum target for voltage and current of 2.4 MeV and 55 kA, respectively. A set of optical diagnostics were fielded in all of the experiments, including a UV-visible spectrometers and a fast imaging. The imaging data obtained during the experiment allowed for the ablated species velocity to be determined. based on spectroscopic analysis, the light emission was attributed to aluminum and tantalum excited atoms and ions. The analysis of this time-integrated spectrum based on radiative transfer model clearly unveiled two distinct regions of the plasma over its expansion: a hot core surrounded by a cold vapor. A quantitative analysis of these results is presented.

  10. Experimental observation of acoustic emissions generated by a pulsed proton beam from a hospital-based clinical cyclotron

    Energy Technology Data Exchange (ETDEWEB)

    Jones, Kevin C.; Solberg, Timothy D.; Avery, Stephen, E-mail: Stephen.Avery@uphs.upenn.edu [Department of Radiation Oncology, University of Pennsylvania, Philadelphia, Pennsylvania 19104 (United States); Vander Stappen, François; Janssens, Guillaume; Prieels, Damien [Ion Beam Applications SA, Louvain-la-Neuve 1348 (Belgium); Bawiec, Christopher R.; Lewin, Peter A. [School of Biomedical Engineering, Drexel University, Philadelphia, Pennsylvania 19104 (United States); Sehgal, Chandra M. [Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania 19104 (United States)

    2015-12-15

    Purpose: To measure the acoustic signal generated by a pulsed proton spill from a hospital-based clinical cyclotron. Methods: An electronic function generator modulated the IBA C230 isochronous cyclotron to create a pulsed proton beam. The acoustic emissions generated by the proton beam were measured in water using a hydrophone. The acoustic measurements were repeated with increasing proton current and increasing distance between detector and beam. Results: The cyclotron generated proton spills with rise times of 18 μs and a maximum measured instantaneous proton current of 790 nA. Acoustic emissions generated by the proton energy deposition were measured to be on the order of mPa. The origin of the acoustic wave was identified as the proton beam based on the correlation between acoustic emission arrival time and distance between the hydrophone and proton beam. The acoustic frequency spectrum peaked at 10 kHz, and the acoustic pressure amplitude increased monotonically with increasing proton current. Conclusions: The authors report the first observation of acoustic emissions generated by a proton beam from a hospital-based clinical cyclotron. When modulated by an electronic function generator, the cyclotron is capable of creating proton spills with fast rise times (18 μs) and high instantaneous currents (790 nA). Measurements of the proton-generated acoustic emissions in a clinical setting may provide a method for in vivo proton range verification and patient monitoring.

  11. Measurements of fast electron beams and soft X-ray emission from plasma-focus experiments

    Directory of Open Access Journals (Sweden)

    Surała Władysław

    2016-06-01

    Full Text Available The paper reports results of the recent experimental studies of pulsed electron beams and soft X-rays in plasma-focus (PF experiments carried out within a modified PF-360U facility at the NCBJ, Poland. Particular attention was focused on time-resolved measurements of the fast electron beams by means of two different magnetic analyzers, which could record electrons of energy ranging from about 41 keV to about 715 keV in several (6 or 8 measuring channels. For discharges performed with the pure deuterium filling, many strong electron signals were recorded in all the measuring channels. Those signals were well correlated with the first hard X-ray pulse detected by an external scintillation neutron-counter. In some of the analyzer channels, electron spikes (lasting about dozens of nanoseconds and appearing in different instants after the current peculiarity (so-called current dip were also recorded. For several discharges, fast ion beams, which were emitted along the z-axis and recorded with nuclear track detectors, were also investigated. Those measurements confirmed a multibeam character of the ion emission. The time-integrated soft X-ray images, which were taken side-on by means of a pinhole camera and sensitive X-ray films, showed the appearance of some filamentary structures and so-called hot spots. The application of small amounts of admixtures of different heavy noble gases, i.e. of argon (4.8% volumetric, krypton (1.6% volumetric, or xenon (0.8% volumetric, decreased intensity of the recorded electron beams, but increased intensity of the soft X-ray emission and showed more distinct and numerous hot spots. The recorded electron spikes have been explained as signals produced by quasi-mono-energetic microbeams emitted from tiny sources (probably plasma diodes, which can be formed near the observed hot spots.

  12. Ion beam emission within a low energy focus plasma (0.1 kJ) operating with hydrogen

    Energy Technology Data Exchange (ETDEWEB)

    El-Aragi, Gamal E. [Nuclear Research Center, Cairo (Egypt). Plasma Physics and Nuclear Fusion Dept.

    2010-06-15

    An investigation of energetic ion beam emission from a low energy plasma focus (0.1 kJ Mather type) device operating with hydrogen gas is studied. The ion beam emission is investigated using time-integrated and time-resolved detectors. The present plasma focus device is powered by a capacitor bank of 1 {mu}F at 18 kV maximum charging voltage. The correlation of ion beam intensity with filling gas pressure indicates that the beam emission is maximized at the optimum pressure for the focus formation at peak current. Energy of ions is determined with a time-of-flight (TOF) method, taking into account distance from the center electrode to the detection plane. (orig.)

  13. Spectroscopy of neutron-rich hypernucleus, $^{7}_{\\Lambda}$He by electron beam

    CERN Document Server

    Gogami, T; Kawama, D; Achenbach, P; Ahmidouch, A; Albayrak, I; Androic, D; Asaturyan, A; Asaturyan, R; Ates, O; Baturin, P; Badui, R; Boeglin, W; Bono, J; Brash, E; Carter, P; Chiba, A; Christy, E; Danagoulian, S; De Leo, R; Doi, D; Elaasar, M; Ent, R; Fujii, Y; Fujita, M; Furic, M; Gabrielyan, M; Gan, L; Garibaldi, F; Gaskell, D; Gasparian, A; Han, Y; Hashimoto, O; Horn, T; Hu, B; Hungerford, Ed V; Jones, M; Kanda, H; Kaneta, M; Kato, S; Kawai, M; Khanal, H; Kohl, M; Liyanage, A; Luo, W; Maeda, K; Margaryan, A; Markowitz, P; Maruta, T; Matsumura, A; Maxwell, V; Mkrtchyan, A; Mkrtchyan, H; Nagao, S; Nakamura, S N; Narayan, A; Neville, C; Niculescu, G; Niculescu, M I; Nunez, A; Nuruzzaman,; Okayasu, Y; Petkovic, T; Pochodzalla, J; Qiu, X; Reinhold, J; Rodriguez, V M; Samanta, C; Sawatzky, B; Seva, T; Shichijo, A; Tadevosyan, V; Tang, L; Taniya, N; Tsukada, K; Veilleux, M; Vulcan, W; Wesselmann, F R; Wood, S A; Yamamoto, T; Ya, L; Ye, Z; Yokota, K; Yuan, L; Zhamkochyan, S; Zhu, L

    2016-01-01

    The missing mass spectroscopy of the $^{7}_{\\Lambda}$He hypernucleus was performed, using the $^{7}$Li$(e,e^{\\prime}K^{+})^{7}_{\\Lambda}$He reaction at JLab Hall-C. The $\\Lambda$ binding energy of the ground state (1/2$^{+}$) was determined with a smaller error than that of the previous measurement, being $B_{\\Lambda}$ = 5.55 $\\pm$ 0.10(stat.) $\\pm$ 0.11(sys.) MeV. The experiment also provided new insight into charge symmetry breaking in p-shell hypernuclear systems. Finally, a peak at $B_{\\Lambda}$ = 3.65 $\\pm$ 0.20(stat.) $\\pm$ 0.11(sys.) MeV was observed and assigned as a mixture of 3/2$^{+}$ and 5/2$^{+}$ states, confirming the "glue-like" behavior of $\\Lambda$, which makes an unstable state in $^{6}$He stable against neutron emission.

  14. [Study on Ammonia Emission Rules in a Dairy Feedlot Based on Laser Spectroscopy Detection Method].

    Science.gov (United States)

    He, Ying; Zhang, Yu-jun; You, Kun; Wang, Li-ming; Gao, Yan-wei; Xu, Jin-feng; Gao, Zhi-ling; Ma, Wen-qi

    2016-03-01

    It needs on-line monitoring of ammonia concentration on dairy feedlot to disclose ammonia emissions characteristics accurately for reducing ammonia emissions and improving the ecological environment. The on-line monitoring system for ammonia concentration has been designed based on Tunable Diode Laser Absorption Spectroscopy (TDLAS) technology combining with long open-path technology, then the study has been carried out with inverse dispersion technique and the system. The ammonia concentration in-situ has been detected and ammonia emission rules have been analyzed on a dairy feedlot in Baoding in autumn and winter of 2013. The monitoring indicated that the peak of ammonia concentration was 6.11 x 10(-6) in autumn, and that was 6.56 x 10(-6) in winter. The concentration results show that the variation of ammonia concentration had an obvious diurnal periodicity, and the general characteristic of diurnal variation was that the concentration was low in the daytime and was high at night. The ammonia emissions characteristic was obtained with inverse dispersion model that the peak of ammonia emissions velocity appeared at noon. The emission velocity was from 1.48 kg/head/hr to 130.6 kg/head/hr in autumn, and it was from 0.004 5 kg/head/hr to 43.32 kg/head/hr in winter which was lower than that in autumn. The results demonstrated ammonia emissions had certain seasonal differences in dairy feedlot scale. In conclusion, the ammonia concentration was detected with optical technology, and the ammonia emissions results were acquired by inverse dispersion model analysis with large range, high sensitivity, quick response without gas sampling. Thus, it's an effective method for ammonia emissions monitoring in dairy feedlot that provides technical support for scientific breeding.

  15. Electron-Beam Atomic Spectroscopy for In Situ Measurements of Melt Composition for Refractory Metals: Analysis of Fundamental Physics and Plasma Models

    Science.gov (United States)

    Gasper, Paul Joseph; Apelian, Diran

    2015-04-01

    Electron-beam (EB) melting is used for the processing of refractory metals, such as Ta, Nb, Mo, and W. These metals have high value and are critical to many industries, including the semiconductor, aerospace, and nuclear industries. EB melting can also purify secondary feedstock, enabling the recovery and recycling of these materials. Currently, there is no method for measuring melt composition in situ during EB melting. Optical emission spectroscopy of the plasma generated by EB impact with vapor above the melt, a technique here termed electron-beam atomic spectroscopy, can be used to measure melt composition in situ, allowing for analysis of melt dynamics, facilitating improvement of EB melting processes and aiding recycling and recovery of these critical and high-value metals. This paper reviews the physics of the plasma generation by EB impact by characterizing the densities and energies of electrons, ions, and neutrals, and describing the interactions between them. Then several plasma models are introduced and their suitability to this application analyzed. Lastly, a potential method for calibration-free composition measurement is described and the challenges for implementation addressed.

  16. Emission control of InGaN nanocolumns grown by molecular-beam epitaxy on Si(111) substrates

    Energy Technology Data Exchange (ETDEWEB)

    Albert, S.; Bengoechea-Encabo, A.; Sanchez-Garcia, M. A.; Calleja, E. [ISOM and Departamento de Ingenieria Electronica, ETSI Telecomunicacion, Universidad Politecnica de Madrid, Ciudad Universitaria s/n, 28040 Madrid (Spain); Lefebvre, P. [ISOM and Departamento de Ingenieria Electronica, ETSI Telecomunicacion, Universidad Politecnica de Madrid, Ciudad Universitaria s/n, 28040 Madrid (Spain); Universite Montpellier 2, F-34095 Montpellier, Cedex 5 (France); Jahn, U.; Trampert, A. [Paul-Drude-Institut fuer Festkoeperelektronik, Hausvogteiplatz 5-7, 10117 Berlin (Germany)

    2011-09-26

    This work studies the effect of the growth temperature on the morphology and emission characteristics of self-assembled InGaN nanocolumns grown by plasma assisted molecular beam epitaxy. Morphology changes are assessed by scanning electron microscopy, while emission is measured by photoluminescence. Within the growth temperature range of 750 to 650 deg. C, an increase in In incorporation for decreasing temperature is observed. This effect allows tailoring the InGaN nanocolumns emission line shape by using temperature gradients during growth. Depending on the gradient rate, span, and sign, broad emission line shapes are obtained, covering the yellow to green range, even yielding white emission.

  17. 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.

  18. Issues in deep ocean collinear double-pulse laser induced breakdown spectroscopy: Dependence of emission intensity and inter-pulse delay on solution pressure

    Energy Technology Data Exchange (ETDEWEB)

    Lawrence-Snyder, Marion; Scaffidi, Jonathan P.; Pearman, William F.; Gordon, Christopher M.; Angel, S. Michael

    2014-09-01

    Double-pulse laser-induced breakdown spectroscopy (DP-LIBS) with a collinear laser beam orientation is shown for high-pressure bulk aqueous solutions (up to 50 bar) along with bubble and plasma images. These investigations reveal that the emission plasma is quenched much more rapidly in solution requiring much shorter detector gate delays than for typical LIBS measurements in air. Also, the emission is inversely proportional to solution pressure, and the most intense emission at all pressures occurs when the laser-induced vapor bubble is at a maximum diameter. It is also shown that the laser-induced bubble grows initially at the same rate for all solution pressures, collapsing more quickly as the pressure is increased. Intense emission is best obtained for conditions where the laser-induced bubble formed by the first laser pulse is small and spherically shaped. - Highlights: • Collinear double-pulse LIBS is shown for 50 bar bulk aqueous solutions. • LIBS plasma in solution is much more rapidly quenched than a LIBS plasma in air. • For DP LIBS, the emission is inversely proportional to solution pressure. • Laser-induced bubble growth rate is the same at all solution pressures. • Large spherical laser-induced bubbles produce the strongest DP LIBS emission.

  19. Gamma ray tracking with the AGATA demonstrator. A novel approach for in-beam spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Birkenbach, Benedikt

    2014-04-11

    PRISMA. The γ-rays were detected with the AGATA demonstrator consisting of five AGATA triple cluster detectors. An additional micro channel plate detector for particle detection was mounted inside the scattering chamber in order to request kinematic coincidences. The analysis procedures for the two complex sub-detectors AGATA and PRISMA were extended and adapted to the specific requirements of this new approach for actinide spectroscopy. First the complex analysis of the magnetic spectrometer PRISMA and solutions for unexpected detector behaviour like time drifts and aberration corrections are described. As a result the individual isotopes of elements from Barium to Tellurium were identified confirming the very high quality of the PRISMA spectrometer and its design parameters. The analysis of the γ-ray spectra comprised a detailed PSA and GRT analysis of the AGATA demonstrator. This analysis included also data analysis developments for the AGATA collaboration. The data of the AGATA demonstrator, the PRISMA spectrometer and the ancillary detectors were merged to obtain background free Doppler corrected spectra for the beam- and target-like reaction products. The simultaneous Doppler correction for beam and target-like ions included an elaborate optimization procedure for unobservable experimental parameters. The γ-ray spectra for the individual isotopes is consistent with the isotope identification of the PRISMA analysis. For the beam like particles γ-ray spectra of the isotopes {sup 128-139}Xe are presented and discussed. For the target like nuclei γ-ray spectra of the isotopes {sup 236-240}U are deduced. By gating on the remaining excitation energy after the multi-nucleon transfer reaction the neutron evaporation and fission of the excited actinide nuclei were suppressed. Coincidences between AGATA and PRISMA were exploited for the first time together with the particle coincidence between beam- and target-like nuclei. These triple coincidences allowed further

  20. Parameters Optimization of Laser-Induced Breakdown Spectroscopy Experimental Setup for the Case with Beam Expander

    Science.gov (United States)

    Wang, Xin; Zhang, Lei; Fan, Juanjuan; Li, Yufang; Gong, Yao; Dong, Lei; Ma, Weiguang; Yin, Wangbao; Jia, Suotang

    2015-11-01

    Improvement of measurement precision and repeatability is one of the issues currently faced by the laser-induced breakdown spectroscopy (LIBS) technique, which is expected to be capable of precise and accurate quantitative analysis. It was found that there was great potential to improve the signal quality and repeatability by reducing the laser beam divergence angle using a suitable beam expander (BE). In the present work, the influences of several experimental parameters for the case with BE are studied in order to optimize the analytical performances: the signal to noise ratio (SNR) and the relative standard deviation (RSD). We demonstrate that by selecting the optimal experimental parameters, the BE-included LIBS setup can give higher SNR and lower RSD values of the line intensity normalized by the whole spectrum area. For validation purposes, support vector machine (SVM) regression combined with principal component analysis (PCA) was used to establish a calibration model to realize the quantitative analysis of the ash content. Good agreement has been found between the laboratory measurement results from the LIBS method and those from the traditional method. The measurement accuracy presented here for ash content analysis is estimated to be 0.31%, while the average relative error is 2.36%. supported by the 973 Program of China (No. 2012CB921603), National Natural Science Foundation of China (Nos. 61475093, 61127017, 61178009, 61108030, 61378047, 61275213, 61475093, and 61205216), the National Key Technology R&D Program of China (No. 2013BAC14B01), the Shanxi Natural Science Foundation (Nos. 2013021004-1 and 2012021022-1), the Shanxi Scholarship Council of China (Nos. 2013-011 and 2013-01), and the Program for the Outstanding Innovative Teams of Higher Learning Institutions of Shanxi, China

  1. Characterisation of a micro-plasma device sensor using electrical measurements and emission spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Mariotti, D

    2002-04-01

    This thesis reports on research undertaken on the characterisation of a micro-plasma device to be used for gas analysis by mean of plasma emission spectroscopy. The work covers aspects related to the micro-plasma electrical and optical emission parameters, and their importance for the utilisation of the micro-plasma device in gas analysis. Experimental results have been used to analyse the fundamental micro-plasma processes and to develop a model, which could provide additional information. This dissertation contains a general literature review of topics related to plasma physics, plasma emission spectroscopy, gas analysis (chemical analysis and artificial olfaction) and other micro-plasma applications. Experimental work focuses on two main areas: electrical measurements and emission measurements. Firstly, electrical measurements are taken and interpretations are given. Where necessary, new theoretical treatments are suggested in order to describe better the physical phenomena. Plasma emission has been considered under different working conditions. This allowed the characterisation of the micro-plasma emission and also a better understanding of the micro-plasma processes. On the basis of the experimental data obtained and other assumptions a model has been developed. A computer simulation based on this model provided additional useful information on the micro- plasma behaviour. The first fundamental implication of this new research is the peculiar behaviour of the micro-plasma. This micro-plasma exhibited deviations from Paschen law and strong dependency on cathode material, which contributed to the formation of a low current stable regime. These results have been followed by physical interpretations and theoretical descriptions. The second implication is the establishment of the boundaries and of the influencing parameters for plasma emission spectroscopy as an analytical tool in this particular micro-plasma. From the applied perspective this study has shown that

  2. Ultrafast Time-Resolved Hard X-Ray Emission Spectroscopy on a Tabletop

    Science.gov (United States)

    Miaja-Avila, Luis; O'Neil, Galen C.; Joe, Young I.; Alpert, Bradley K.; Damrauer, Niels H.; Doriese, William B.; Fatur, Steven M.; Fowler, Joseph W.; Hilton, Gene C.; Jimenez, Ralph; Reintsema, Carl D.; Schmidt, Daniel R.; Silverman, Kevin L.; Swetz, Daniel S.; Tatsuno, Hideyuki; Ullom, Joel N.

    2016-07-01

    Experimental tools capable of monitoring both atomic and electronic structure on ultrafast (femtosecond to picosecond) time scales are needed for investigating photophysical processes fundamental to light harvesting, photocatalysis, energy and data storage, and optical display technologies. Time-resolved hard x-ray (>3 keV ) spectroscopies have proven valuable for these measurements due to their elemental specificity and sensitivity to geometric and electronic structures. Here, we present the first tabletop apparatus capable of performing time-resolved x-ray emission spectroscopy. The time resolution of the apparatus is better than 6 ps. By combining a compact laser-driven plasma source with a highly efficient array of microcalorimeter x-ray detectors, we are able to observe photoinduced spin changes in an archetypal polypyridyl iron complex [Fe (2 ,2'-bipyridine)3]2 + and accurately measure the lifetime of the quintet spin state. Our results demonstrate that ultrafast hard x-ray emission spectroscopy is no longer confined to large facilities and now can be performed in conventional laboratories with 10 times better time resolution than at synchrotrons. Our results are enabled, in part, by a 100- to 1000-fold increase in x-ray collection efficiency compared to current techniques.

  3. Pulse-periodic generation of supershort avalanche electron beams and X-ray emission

    Science.gov (United States)

    Baksht, E. Kh.; Burachenko, A. G.; Erofeev, M. V.; Tarasenko, V. F.

    2014-05-01

    Pulse-periodic generation of supershort avalanche electron beams (SAEBs) and X-ray emission in nitrogen, as well as the transition from a single-pulse mode to a pulse-periodic mode with a high repetition frequency, was studied experimentally. It is shown that, in the pulse-periodic mode, the full width at halfmaximum of the SAEB is larger and the decrease rate of the gap voltage is lower than those in the single-pulse mode. It is found that, when the front duration of the voltage pulse at a nitrogen pressure of 90 Torr decreases from 2.5 to 0.3 ns, the X-ray exposure dose in the pulse-periodic mode increases by more than one order of magnitude and the number of SAEB electrons also increases. It is shown that, in the pulse-periodic mode of a diffuse discharge, gas heating in the discharge gap results in a severalfold increase in the SAEB amplitude (the number of electrons in the beam). At a generator voltage of 25 kV, nitrogen pressure of 90 Torr, and pulse repetition frequency of 3.5 kHz, a runaway electron beam was detected behind the anode foil.

  4. [Photodissociation of Acetylene and Acetone using Step-Scan Time-Resolved FTIR Emission Spectroscopy

    Science.gov (United States)

    McLaren, Ian A.; Wrobel, Jacek D.

    1997-01-01

    The photodissociation of acetylene and acetone was investigated as a function of added quenching gas pressures using step-scan time-resolved FTIR emission spectroscopy. Its main components consist of Bruker IFS88, step-scan Fourier Transform Infrared (FTIR) spectrometer coupled to a flow cell equipped with Welsh collection optics. Vibrationally excited C2H radicals were produced from the photodissociation of acetylene in the unfocused experiments. The infrared (IR) emission from these excited C2H radicals was investigated as a function of added argon pressure. Argon quenching rate constants for all C2H emission bands are of the order of 10(exp -13)cc/molecule.sec. Quenching of these radicals by acetylene is efficient, with a rate constant in the range of 10(exp -11) cc/molecule.sec. The relative intensity of the different C2H emission bands did not change with the increasing argon or acetylene pressure. However, the overall IR emission intensity decreased, for example, by more than 50% when the argon partial pressure was raised from 0.2 to 2 Torr at fixed precursor pressure of 160mTorr. These observations provide evidence for the formation of a metastable C2H2 species, which are collisionally quenched by argon or acetylene. Problems encountered in the course of the experimental work are also described.

  5. 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.

  6. Nuclear Ground State Properties in Strontium by Fast Beam Laser Spectroscopy

    CERN Multimedia

    2002-01-01

    Hyperfine structures and isotope shifts of strontium isotopes with A=78 to A=100 were measured by collinear fast beam laser spectroscopy. Nuclear spins, moments and changes in mean square charge radii are extracted from the data. The spins and moments of most of the odd isotopes are explained in the framework of the single particle model. The changes in mean square charge radii show a decrease with increasing neutron number below the N=50 shell closure. Above N=50 the charge radii increase regularly up to N=59 before revealing a strong discontinuity, indicating the onset of strong ground state deformation. A comparison of the droplet model shows that for the transitional isotopes below and above N=50, the zero point quadrupole motion describes part of the observed shell effect. Calculations carried out in the Hartree-Fock plus BCS model suggest an additional change in the surface region of the charge distribution at spherical shape. From these calculations it is furthermore proposed, that the isotopes $^7

  7. Helium implanted Eurofer97 characterized by positron beam Doppler broadening and Thermal Desorption Spectroscopy

    Science.gov (United States)

    Carvalho, I.; Schut, H.; Fedorov, A.; Luzginova, N.; Desgardin, P.; Sietsma, J.

    2013-11-01

    Reduced Activation Ferritic/Martensitic steels are being extensively studied because of their foreseen application in fusion and Generation IV fission reactors. To produce irradiation induced defects, Eurofer97 samples were implanted with helium at energies of 500 keV and 2 MeV and doses of 1 × 1015-1016 He/cm2, creating atomic displacements in the range 0.07-0.08 dpa. The implantation induced defects were characterized by positron beam Doppler Broadening (DB) and Thermal Desorption Spectroscopy (TDS). Results show that up to ˜600 K peaks that can be attributed to He desorption from overpressured HenVm (n > m) clusters and vacancy assisted mechanism in the case of helium in the substitutional position. The temperature range 600-1200 K is related to the formation of larger clusters HenVm (n < m). The dissociation of the HeV and the phase transition attributed to a sharp peak in the TDS spectra at 1200 K. Above this temperature, the release of helium from bubbles is observed.

  8. A rapid screening method for heavy metals in biological materials by emission spectroscopy.

    Science.gov (United States)

    Blacklock, E C; Sadler, P A

    1981-06-02

    A semi-quantitative screening method for heavy metals in biological material is described. The metals are complexed with ammonium pyrrolidine dithiocarbamate, sodium diethyl dithiocarbamate and potassium sodium tartrate. The solutions are adjusted to pH 4 and then extracted into chloroform. The chloroform phase is evaporated onto a matrix mixture of lithium fluoride and graphite. The sample is analysed by direct current arc emission spectroscopy using a 3 metre grating spectrograph. The spectra are recorded on a photographic plate. The method is developed on aqueous and spiked samples and then applied to in vivo samples containing toxic levels of heavy metals. Atomic absorption spectroscopy is used to check standard concentrations and to monitor the efficiency of the extraction procedure.

  9. Excitation-emission matrices and synchronous fluorescence spectroscopy for the diagnosis of gastrointestinal cancers

    Science.gov (United States)

    Genova, Ts; Borisova, E.; Penkov, N.; Vladimirov, B.; Zhelyazkova, A.; Avramov, L.

    2016-06-01

    We report the development of an improved fluorescence technique for cancer diagnostics in the gastrointestinal tract. We investigate the fluorescence of ex vivo colorectal (cancerous and healthy) tissue samples using excitation-emission matrix (EEM) and synchronous fluorescence spectroscopy (SFS) steady-state approaches. The obtained results are processed for revealing characteristic fluorescence spectral features with a valuable diagnostic meaning. The main tissue fluorophores, contributing to the observed fluorescence, are tyrosine, tryptophan, NADH, FAD, collagen and elastin. Based on the results of the Mann-Whitney test as useful parameters for differentiation of gastrointestinal cancer from normal mucosa, we suggest using excitation wavelengths in the range 300 - 360 nm for fluorescence spectroscopy and wavelengths intervals of 60 nm and 90 nm for SFS.

  10. Application of {sup 57}Co emission Moessbauer spectroscopy to studying biocomplexes in frozen solutions

    Energy Technology Data Exchange (ETDEWEB)

    Kamnev, A. A., E-mail: aakamnev@ibppm.sgu.ru [Laboratory of Biochemistry of Plant-Bacterial Symbioses, Institute of Biochemistry and Physiology of Plants and Microorganisms, Russian Academy of Sciences (Russian Federation); Kulikov, L. A.; Perfiliev, Yu. D. [M.V. Lomonosov Moscow State University, Laboratory of Nuclear Chemistry Techniques, Department of Radiochemistry, Faculty of Chemistry (Russian Federation); Antonyuk, L. P. [Laboratory of Biochemistry of Plant-Bacterial Symbioses, Institute of Biochemistry and Physiology of Plants and Microorganisms, Russian Academy of Sciences (Russian Federation); Kuzmann, E.; Vertes, A. [Eoetvoes Lorand University, Research Group for Nuclear Techniques in Structural Chemistry, Hungarian Academy of Sciences, Department of Nuclear Chemistry (Hungary)

    2005-09-15

    Emission Moessbauer spectroscopy with the {sup 57}Co isotope was used to study very dilute rapidly frozen aqueous solutions of cobalt(II) complexes with low-molecular-weight biomolecules (aromatic amino acids - anthranilic acid and L-tryptophan) and within a sophisticated biopolymer, bacterial glutamine synthetase, a key enzyme of nitrogen metabolism. The appearance of after-effects of the {sup 57}Co{sup {yields}57}Fe nuclear transformation as well as the coordination properties of the cation and the ligands in the complexes are discussed on the basis of their Moessbauer parameters.

  11. Assessing topographic cutaneous autofluorescence variation using fluorescence UV and visible excitation emission matrix (EEM) spectroscopy

    Science.gov (United States)

    Zhao, Jianhua; Zandi, Soodabeh; Feng, Florina; Zeng, Haishan; McLean, David I.; Lui, Harvey

    2011-03-01

    Cutaneous autofluorescence properties were systematically studied using fluorescence excitation emission matrix spectroscopy. Twenty-six healthy subjects with a mean age of 34 (range 21-74) participated in this study. The fluorescence of major skin fluorophores such as tryptophan, collagen, elastin and NADH could be readily identified. On average, facial skin shows strong tryptophan and measurable porphyrin fluorescence; the palm and nail show strong tryptophan and keratin fluorescence. These results demonstrate that regional topographic variations exist not only in the amount of fluorescence but also in the relative distribution of fluorophores in normal skin. Moreover this provides a basis for future interpretation of autofluorescence in diseased skin.

  12. Application of 57Co emission Mössbauer spectroscopy to studying biocomplexes in frozen solutions

    Science.gov (United States)

    Kamnev, A. A.; Kulikov, L. A.; Perfiliev, Yu. D.; Antonyuk, L. P.; Kuzmann, E.; Vértes, A.

    2005-09-01

    Emission Mössbauer spectroscopy with the 57Co isotope was used to study very dilute rapidly frozen aqueous solutions of cobalt(II) complexes with low-molecular-weight biomolecules (aromatic amino acids anthranilic acid and L-tryptophan) and within a sophisticated biopolymer, bacterial glutamine synthetase, a key enzyme of nitrogen metabolism. The appearance of after-effects of the 57Co→57Fe nuclear transformation as well as the coordination properties of the cation and the ligands in the complexes are discussed on the basis of their Mössbauer parameters.

  13. Remote gas analysis of aircraft exhausts using FTIR-emission-spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Heland, J.; Schaefer, K. [Fraunhofer Inst. for Atmospheric Environmental Research, Garmisch-Partenkirchen (Germany)

    1997-12-31

    FITR emission spectroscopy as a remote sensing multi-component analyzing technique was investigated to determine the composition of aircraft exhausts at ground level. A multi-layer radiative transfer interpretation software based on a line-by-line computer algorithm using the HITRAN data base was developed. Measurements were carried out with different engine types to determine the traceable gas species and their detection limits. Finally validation measurements were made to compare the results of the system to those of conventional equipment. (author) 8 refs.

  14. LZIFU: an emission-line fitting toolkit for integral field spectroscopy data

    CERN Document Server

    Ho, I-Ting; Groves, Brent; Rich, Jeffrey A; Rupke, David S N; Hampton, Elise; Kewley, Lisa J; Bland-Hawthorn, Joss; Croom, Scott M; Richards, Samuel; Schaefer, Adam L; Sharp, Rob; Sweet, Sarah M

    2016-01-01

    We present LZIFU (LaZy-IFU), an IDL toolkit for fitting multiple emission lines simultaneously in integral field spectroscopy (IFS) data. LZIFU is useful for the investigation of the dynamical, physical and chemical properties of gas in galaxies. LZIFU has already been applied to many world-class IFS instruments and large IFS surveys, including the Wide Field Spectrograph, the new Multi Unit Spectroscopic Explorer (MUSE), the Calar Alto Legacy Integral Field Area (CALIFA) survey, the Sydney-Australian-astronomical-observatory Multi-object Integral-field spectrograph (SAMI) Galaxy Survey. Here we describe in detail the structure of the toolkit, and how the line fluxes and flux uncertainties are determined, including the possibility of having multiple distinct kinematic components. We quantify the performance of LZIFU, demonstrating its accuracy and robustness. We also show examples of applying LZIFU to CALIFA and SAMI data to construct emission line and kinematic maps, and investigate complex, skewed line prof...

  15. Optical Emission Spectroscopy of an Atmospheric Pressure Plasma Jet During Tooth Bleaching Gel Treatment.

    Science.gov (United States)

    Šantak, Vedran; Zaplotnik, Rok; Tarle, Zrinka; Milošević, Slobodan

    2015-11-01

    Optical emission spectroscopy was performed during atmospheric pressure plasma needle helium jet treatment of various tooth-bleaching gels. When the gel sample was inserted under the plasma plume, the intensity of all the spectral features increased approximately two times near the plasma needle tip and up to two orders of magnitude near the sample surface. The color change of the hydroxylapatite pastille treated with bleaching gels in conjunction with the atmospheric pressure plasma jet was found to be in correlation with the intensity of OH emission band (309 nm). Using argon as an additive to helium flow (2 L/min), a linear increase (up to four times) of OH intensity and, consequently, whitening (up to 10%) of the pastilles was achieved. An atmospheric pressure plasma jet activates bleaching gel, accelerates OH production, and accelerates tooth bleaching (up to six times faster).

  16. X-ray absorption and X-ray emission spectroscopy theory and applications

    CERN Document Server

    Lamberti, Carlo

    2016-01-01

    During the last two decades, remarkable and often spectacular progress has been made in the methodological and instrumental aspects of x–ray absorption and emission spectroscopy. This progress includes considerable technological improvements in the design and production of detectors especially with the development and expansion of large-scale synchrotron reactors All this has resulted in improved analytical performance and new applications, as well as in the perspective of a dramatic enhancement in the potential of x–ray based analysis techniques for the near future. This comprehensive two-volume treatise features articles that explain the phenomena and describe examples of X–ray absorption and emission applications in several fields, including chemistry, biochemistry, catalysis, amorphous and liquid systems, synchrotron radiation, and surface phenomena. Contributors explain the underlying theory, how to set up X–ray absorption experiments, and how to analyze the details of the resulting spectra. X-R...

  17. Characterization of dielectric barrier discharge in air applying current measurement, numerical simulation and emission spectroscopy

    CERN Document Server

    Rajasekaran, Priyadarshini; Awakowicz, Peter

    2012-01-01

    Dielectric barrier discharge (DBD) in air is characterized applying current measurement, numerical simulation and optical emission spectroscopy (OES). For OES, a non-calibrated spectrometer is used. This diagnostic method is applicable when cross-sectional area of the active plasma volume and current density can be determined. The nitrogen emission in the spectral range of 380 nm- 406 nm is used for OES diagnostics. Electric field in the active plasma volume is determined applying the measured spectrum, well-known Frank-Condon factors for nitrogen transitions and numerically- simulated electron distribution functions. The measured electric current density is used for determination of electron density in plasma. Using the determined plasma parameters, the dissociation rate of nitrogen and oxygen in active plasma volume are calculated, which can be used by simulation of the chemical kinetics.

  18. Relativistic atomic beam spectroscopy 2. Appendix A: Progress report, July 1, 1989--June 30, 1992: Final report

    Energy Technology Data Exchange (ETDEWEB)

    Bryant, H.C.

    1992-07-01

    This work supported by the Division of Chemical Sciences, Office of Basic Energy Services, Office of Energy Research, US Department of Energy during the period July 1, 1989 to June 30, 1992, resulted in noteworthy scientific results in three categories which we shall discuss in turn: The spectroscopy of high-lying doubly-excited states of H{sup {minus}}, interactions with thin foils, and multiphoton processes. Radiological safety concerns and slow beam studies are also briefly discussed.

  19. Injectable silver nanosensors: in vivo dosimetry for external beam radiotherapy using positron emission tomography

    Science.gov (United States)

    Christensen, A. N.; Rydhög, J. S.; Søndergaard, R. V.; Andresen, T. L.; Holm, S.; Munck Af Rosenschöld, P.; Conradsen, K.; Jølck, R. I.

    2016-05-01

    Development of safe and efficient radiotherapy routines requires quantification of the delivered absorbed dose to the cancer tissue in individual patients. In vivo dosimetry can provide accurate information about the absorbed dose delivered during treatment. In the current study, a novel silver-nanosensor formulation based on poly(vinylpyrrolidinone)-coated silver nanoparticles formulated in a gelation matrix composed of sucrose acetate isobutyrate has been developed for use as an in vivo dosimeter for external beam radiotherapy. In situ photonuclear reactions trigger the formation of radioactive 106Ag, which enables post treatment verification of the delivered dose using positron emission tomography imaging. The silver-nanosensor was investigated in a tissue equivalent thorax phantom using clinical settings and workflow for both standard fractionated radiotherapy (2 Gy) and stereotactic radiotherapy (10- and 22 Gy) in a high-energy beam setting (18 MV). The developed silver-nanosensor provided high radiopacity on the planning CT-scans sufficient for patient positioning in image-guided radiotherapy and provided dosimetric information about the absorbed dose with a 10% and 8% standard deviation for the stereotactic regimens, 10 and 22 Gy, respectively.Development of safe and efficient radiotherapy routines requires quantification of the delivered absorbed dose to the cancer tissue in individual patients. In vivo dosimetry can provide accurate information about the absorbed dose delivered during treatment. In the current study, a novel silver-nanosensor formulation based on poly(vinylpyrrolidinone)-coated silver nanoparticles formulated in a gelation matrix composed of sucrose acetate isobutyrate has been developed for use as an in vivo dosimeter for external beam radiotherapy. In situ photonuclear reactions trigger the formation of radioactive 106Ag, which enables post treatment verification of the delivered dose using positron emission tomography imaging. The

  20. Laser-induced optical breakdown spectroscopy of polymer materials based on evaluation of molecular emission bands

    Science.gov (United States)

    Trautner, Stefan; Jasik, Juraj; Parigger, Christian G.; Pedarnig, Johannes D.; Spendelhofer, Wolfgang; Lackner, Johannes; Veis, Pavel; Heitz, Johannes

    2017-03-01

    Laser-induced breakdown spectroscopy (LIBS) for composition analysis of polymer materials results in optical spectra containing atomic and ionic emission lines as well as molecular emission bands. In the present work, the molecular bands are analyzed to obtain spectroscopic information about the plasma state in an effort to quantify the content of different elements in the polymers. Polyethylene (PE) and a rubber material from tire production are investigated employing 157 nm F2 laser and 532 nm Nd:YAG laser ablation in nitrogen and argon gas background or in air. The optical detection reaches from ultraviolet (UV) over the visible (VIS) to the near infrared (NIR) spectral range. In the UV/VIS range, intense molecular emissions, C2 Swan and CN violet bands, are measured with an Echelle spectrometer equipped with an intensified CCD camera. The measured molecular emission spectra can be fitted by vibrational-rotational transitions by open access programs and data sets with good agreement between measured and fitted spectra. The fits allow determining vibrational-rotational temperatures. A comparison to electronic temperatures Te derived earlier from atomic carbon vacuum-UV (VUV) emission lines show differences, which can be related to different locations of the atomic and molecular species in the expanding plasma plume. In the NIR spectral region, we also observe the CN red bands with a conventional CDD Czerny Turner spectrometer. The emission of the three strong atomic sulfur lines between 920 and 925 nm is overlapped by these bands. Fitting of the CN red bands allows a separation of both spectral contributions. This makes a quantitative evaluation of sulfur contents in the start material in the order of 1 wt% feasible.

  1. Measuring NMHC and NMOG emissions from motor vehicles via FTIR spectroscopy

    Science.gov (United States)

    Gierczak, Christine A.; Kralik, Lora L.; Mauti, Adolfo; Harwell, Amy L.; Maricq, M. Matti

    2017-02-01

    The determination of non-methane organic gases (NMOG) emissions according to United States Environmental Protection Agency (EPA) regulations is currently a multi-step process requiring separate measurement of various emissions components by a number of independent on-line and off-line techniques. The Fourier transform infrared spectroscopy (FTIR) method described in this paper records all required components using a single instrument. It gives data consistent with the regulatory method, greatly simplifies the process, and provides second by second time resolution. Non-methane hydrocarbons (NMHCs) are measured by identifying a group of hydrocarbons, including oxygenated species, that serve as a surrogate for this class, the members of which are dynamically included if they are present in the exhaust above predetermined threshold levels. This yields an FTIR equivalent measure of NMHC that correlates within 5% to the regulatory flame ionization detection (FID) method. NMOG is then determined per regulatory calculation solely from FTIR recorded emissions of NMHC, ethanol, acetaldehyde, and formaldehyde, yielding emission rates that also correlate within 5% with the reference method. Examples are presented to show how the resulting time resolved data benefit aftertreatment development for light duty vehicles.

  2. Galactic Outflows in Absorption and Emission: Near-UV Spectroscopy of Galaxies at 1

    CERN Document Server

    Erb, Dawn K; Henry, Alaina L; Martin, Crystal L

    2012-01-01

    We study large-scale outflows in a sample of 96 star-forming galaxies at 1spectroscopy of FeII and MgII absorption and emission. The average blueshift of the FeII interstellar absorption lines with respect to the systemic velocity is -85+/-10 km/s at z~1.5, with standard deviation 87 km/s; this is a decrease of a factor of two from the average blueshift measured for far-UV interstellar absorption lines in similarly selected galaxies at z~2. The profiles of the MgII 2796, 2803 lines show much more variety than the FeII profiles, which are always seen in absorption; MgII ranges from strong emission to pure absorption, with emission more common in galaxies with blue UV slopes and at lower stellar masses. Outflow velocities, as traced by the centroids and maximum extent of the absorption lines, increase with increasing stellar mass with 2-3sigma significance, in agreement with previous results. We study fine structure emission from FeII*, finding several lines of evidence in support of t...

  3. Self-corrected sensors based on atomic absorption spectroscopy for atom flux measurements in molecular beam epitaxy

    Energy Technology Data Exchange (ETDEWEB)

    Du, Y., E-mail: yingge.du@pnnl.gov, E-mail: scott.chambers@pnnl.gov; Liyu, A. V. [Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99352 (United States); Droubay, T. C.; Chambers, S. A., E-mail: yingge.du@pnnl.gov, E-mail: scott.chambers@pnnl.gov [Fundamental and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, Washington 99352 (United States); Li, G. [Energy and Environment Directorate, Pacific Northwest National Laboratory, Richland, Washington 99352 (United States)

    2014-04-21

    A high sensitivity atom flux sensor based on atomic absorption spectroscopy has been designed and implemented to control electron beam evaporators and effusion cells in a molecular beam epitaxy system. Using a high-resolution spectrometer and a two-dimensional charge coupled device detector in a double-beam configuration, we employ either a non-resonant line or a resonant line with low cross section from the same hollow cathode lamp as the reference for nearly perfect background correction and baseline drift removal. This setup also significantly shortens the warm-up time needed compared to other sensor technologies and drastically reduces the noise coming from the surrounding environment. In addition, the high-resolution spectrometer allows the most sensitive resonant line to be isolated and used to provide excellent signal-to-noise ratio.

  4. Self-corrected Sensors Based On Atomic Absorption Spectroscopy For Atom Flux Measurements In Molecular Beam Epitaxy

    Energy Technology Data Exchange (ETDEWEB)

    Du, Yingge; Droubay, Timothy C.; Liyu, Andrey V.; Li, Guosheng; Chambers, Scott A.

    2014-04-24

    A high sensitivity atom flux sensor based on atomic absorption spectroscopy has been designed and implemented to control electron beam evaporators and effusion cells in a molecular beam epitaxy system. Using a high-resolution spectrometer and a two-dimensional charge coupled device (CCD) detector in a double-beam configuration, we employ a non-resonant line or a resonant line with lower absorbance from the same hollow cathode lamp as the reference for nearly perfect background correction and baseline drift removal. This setup also significantly shortens the warm-up time needed compared to other sensor technologies and drastically reduces the noise coming from the surrounding environment. In addition, the high-resolution spectrometer allows the most sensitive resonant line to be isolated and used to provide excellent signal-to-noise ratio.

  5. Self-corrected sensors based on atomic absorption spectroscopy for atom flux measurements in molecular beam epitaxy

    Science.gov (United States)

    Du, Y.; Droubay, T. C.; Liyu, A. V.; Li, G.; Chambers, S. A.

    2014-04-01

    A high sensitivity atom flux sensor based on atomic absorption spectroscopy has been designed and implemented to control electron beam evaporators and effusion cells in a molecular beam epitaxy system. Using a high-resolution spectrometer and a two-dimensional charge coupled device detector in a double-beam configuration, we employ either a non-resonant line or a resonant line with low cross section from the same hollow cathode lamp as the reference for nearly perfect background correction and baseline drift removal. This setup also significantly shortens the warm-up time needed compared to other sensor technologies and drastically reduces the noise coming from the surrounding environment. In addition, the high-resolution spectrometer allows the most sensitive resonant line to be isolated and used to provide excellent signal-to-noise ratio.

  6. Revised Landé gJ-factors of some 141Pr II levels using collinear laser ion beam spectroscopy

    Science.gov (United States)

    Werbowy, S.; Windholz, L.

    2017-01-01

    The Zeeman effect of singly ionized praseodymium spectral lines was studied at small magnetic fields up to 334 G, using the high-resolution spectroscopic method of collinear laser-ion-beam spectroscopy (CLIBS), where a collimated fast ion beam is superimposed with a counter propagating laser beam tuned to the desired transition. This nearly Doppler-effect-free technique enables to observe linewidths as low as 100 MHz and thus to record the Zeeman patterns of the hyperfine structure of the investigated spectral lines. From the Zeeman patterns of 21 lines of Pr II lines in the range 570.45-609.038 nm we have re-determined the Landé gJ-factors of 14 levels of the f3 dodd and 16 levels of the f3 p and f2d2even configurations. The obtained experimental Landé factors are compared with available earlier measurements as well as with theoretical calculations.

  7. Optimizing the e-beam profile of a single carbon nanotube field emission device for electric propulsion systems

    Directory of Open Access Journals (Sweden)

    Juliano Fujioka Mologni

    2010-04-01

    Full Text Available Preliminary studies on field emission (FE arrays comprised of carbon nanotubes (CNT as an electron source for electric propulsion system show remarkably promising results. Design parameters for a carbon nanotube (CNT field-emission device operating on triode configuration were numerically simulated and optimized in order to enhance the e-beam focusing quality. An additional focus gate (FG was integrated to the device to control the profile of the emitted e-beam. An axisymmetric finite element model was developed to calculate the electric field distribution on the vacuum region and a modified Fowler-Nordheim (FN equation was used to evaluate the current density emission and the effective emitter area. Afterward, a FE simulation was employed in order to calculate the trajectory of the emitted electrons and define the electron-optical properties of the e-beam. The integration of the FG was fully investigated via computational intelligence techniques. The best performance device according to our simulations presents a collimated e-beam profile that suits well for field emission displays, magnetic field detection and electron microscopy. The automated computational design tool presented in this study strongly benefits the robust design of integrated electron-optical systems for vacuum field emission applications, including electrodynamic tethering and electric propulsion systems.

  8. Superficial dosimetry imaging of Čerenkov emission in electron beam radiotherapy of phantoms

    Science.gov (United States)

    Zhang, Rongxiao; Fox, Colleen J.; Glaser, Adam K.; Gladstone, David J.; Pogue, Brian W.

    2013-08-01

    Čerenkov emission is generated from ionizing radiation in tissue above 264 keV energy. This study presents the first examination of this optical emission as a surrogate for the absorbed superficial dose. Čerenkov emission was imaged from the surface of flat tissue phantoms irradiated with electrons, using a range of field sizes from 6 cm × 6 cm to 20 cm × 20 cm, incident angles from 0° to 50°, and energies from 6 to 18 MeV. The Čerenkov images were compared with the estimated superficial dose in phantoms from direct diode measurements, as well as calculations by Monte Carlo and the treatment planning system. Intensity images showed outstanding linear agreement (R2 = 0.97) with reference data of the known dose for energies from 6 to 18 MeV. When orthogonal delivery was carried out, the in-plane and cross-plane dose distribution comparisons indicated very little difference (±2-4% differences) between the different methods of estimation as compared to Čerenkov light imaging. For an incident angle 50°, the Čerenkov images and Monte Carlo simulation show excellent agreement with the diode data, but the treatment planning system had a larger error (OPT = ±1˜2%, diode = ±2˜3%, TPS = ±6-8% differences) as would be expected. The sampling depth of superficial dosimetry based on Čerenkov radiation has been simulated in a layered skin model, showing the potential of sampling depth tuning by spectral filtering. Taken together, these measurements and simulations indicate that Čerenkov emission imaging might provide a valuable method of superficial dosimetry imaging from incident radiotherapy beams of electrons.

  9. Injectable silver nanosensors: in vivo dosimetry for external beam radiotherapy using positron emission tomography

    DEFF Research Database (Denmark)

    Christensen, Anders Nymark; Rydhög, J. S.; Søndergaard, Rikke Vicki;

    2016-01-01

    Development of safe and efficient radiotherapy routines requires quantification of the delivered absorbed dose to the cancer tissue in individual patients. In vivo dosimetry can provide accurate information about the absorbed dose delivered during treatment. In the current study, a novel silver......-nanosensor formulation based on poly(vinylpyrrolidinone)-coated silver nanoparticles formulated in a gelation matrix composed of sucrose acetate isobutyrate has been developed for use as an in vivo dosimeter for external beam radiotherapy. In situ photonuclear reactions trigger the formation of radioactive (106)Ag......, which enables post treatment verification of the delivered dose using positron emission tomography imaging. The silver-nanosensor was investigated in a tissue equivalent thorax phantom using clinical settings and workflow for both standard fractionated radiotherapy (2 Gy) and stereotactic radiotherapy...

  10. Emission control of InGaN nanocolumns grown by molecular-beam epitaxy on Si(111) substrates

    OpenAIRE

    Albert, S; Bengoechea-Encabo, A.; Lefebvre, P.; Sanchez-Garcia, M. A.; Calleja, E.; Jahn, U.; Trampert, A

    2011-01-01

    International audience; This work studies the effect of the growth temperature on the morphology and emission characteristics of self-assembled InGaN nanocolumns grown by plasma assisted molecular beam epitaxy. Morphology changes are assessed by scanning electron microscopy, while emission is measured by photoluminescence. Within the growth temperature range of 750 to 650°C, an increase in In incorporation for decreasing temperature is observed. This effect allows tailoring the InGaN nanocolu...

  11. 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.

  12. Electron beam technology for multipollutant emissions control from heavy fuel oil-fired boiler.

    Science.gov (United States)

    Chmielewski, Andrzej G; Ostapczuk, Anna; Licki, Janusz

    2010-08-01

    The electron beam treatment technology for purification of exhaust gases from the burning of heavy fuel oil (HFO) mazout with sulfur content approximately 3 wt % was tested at the Institute of Nuclear Chemistry and Technology laboratory plant. The parametric study was conducted to determine the sulfur dioxide (SO2), oxides of nitrogen (NO(x)), and polycyclic aromatic hydrocarbon (PAH) removal efficiency as a function of temperature and humidity of irradiated gases, absorbed irradiation dose, and ammonia stoichiometry process parameters. In the test performed under optimal conditions with an irradiation dose of 12.4 kGy, simultaneous removal efficiencies of approximately 98% for SO2, and 80% for NO(x) were recorded. The simultaneous decrease of PAH and one-ringed aromatic hydrocarbon (benzene, toluene, and xylenes [BTX]) concentrations was observed in the irradiated flue gas. Overall removal efficiencies of approximately 42% for PAHs and 86% for BTXs were achieved with an irradiation dose 5.3 kGy. The decomposition ratio of these compounds increased with an increase of absorbed dose. The decrease of PAH and BTX concentrations was followed by the increase of oxygen-containing aromatic hydrocarbon concentrations. The PAH and BTX decomposition process was initialized through the reaction with hydroxyl radicals that formed in the electron beam irradiated flue gas. Their decomposition process is based on similar principles as the primary reaction concerning SO2 and NO(x) removal; that is, free radicals attack organic compound chains or rings, causing volatile organic compound decomposition. Thus, the electron beam flue gas treatment (EBFGT) technology ensures simultaneous removal of acid (SO2 and NO(x)) and organic (PAH and BTX) pollutants from flue gas emitted from burning of HFO. This technology is a multipollutant emission control technology that can be applied for treatment of flue gas emitted from coal-, lignite-, and HFO-fired boilers. Other thermal processes such

  13. Chemical Modification of Graphene Oxide by Nitrogenation: An X-ray Absorption and Emission Spectroscopy Study

    Science.gov (United States)

    Chuang, Cheng-Hao; Ray, Sekhar C.; Mazumder, Debarati; Sharma, Surbhi; Ganguly, Abhijit; Papakonstantinou, Pagona; Chiou, Jau-Wern; Tsai, Huang-Ming; Shiu, Hung-Wei; Chen, Chia-Hao; Lin, Hong-Ji; Guo, Jinghua; Pong, Way-Faung

    2017-01-01

    Nitrogen-doped graphene oxides (GO:Nx) were synthesized by a partial reduction of graphene oxide (GO) using urea [CO(NH2)2]. Their electronic/bonding structures were investigated using X-ray absorption near-edge structure (XANES), valence-band photoemission spectroscopy (VB-PES), X-ray emission spectroscopy (XES) and resonant inelastic X-ray scattering (RIXS). During GO:Nx synthesis, different nitrogen-bonding species, such as pyrrolic/graphitic-nitrogen, were formed by replacing of oxygen-containing functional groups. At lower N-content (2.7 at%), pyrrolic-N, owing to surface and subsurface diffusion of C, N and NH is deduced from various X-ray spectroscopies. In contrast, at higher N-content (5.0 at%) graphitic nitrogen was formed in which each N-atom trigonally bonds to three distinct sp2-hybridized carbons with substitution of the N-atoms for C atoms in the graphite layer. Upon nitrogen substitution, the total density of state close to Fermi level is increased to raise the valence-band maximum, as revealed by VB-PES spectra, indicating an electron donation from nitrogen, molecular bonding C/N/O coordination or/and lattice structure reorganization in GO:Nx. The well-ordered chemical environments induced by nitrogen dopant are revealed by XANES and RIXS measurements. PMID:28186190

  14. Chemical Modification of Graphene Oxide by Nitrogenation: An X-ray Absorption and Emission Spectroscopy Study

    Science.gov (United States)

    Chuang, Cheng-Hao; Ray, Sekhar C.; Mazumder, Debarati; Sharma, Surbhi; Ganguly, Abhijit; Papakonstantinou, Pagona; Chiou, Jau-Wern; Tsai, Huang-Ming; Shiu, Hung-Wei; Chen, Chia-Hao; Lin, Hong-Ji; Guo, Jinghua; Pong, Way-Faung

    2017-02-01

    Nitrogen-doped graphene oxides (GO:Nx) were synthesized by a partial reduction of graphene oxide (GO) using urea [CO(NH2)2]. Their electronic/bonding structures were investigated using X-ray absorption near-edge structure (XANES), valence-band photoemission spectroscopy (VB-PES), X-ray emission spectroscopy (XES) and resonant inelastic X-ray scattering (RIXS). During GO:Nx synthesis, different nitrogen-bonding species, such as pyrrolic/graphitic-nitrogen, were formed by replacing of oxygen-containing functional groups. At lower N-content (2.7 at%), pyrrolic-N, owing to surface and subsurface diffusion of C, N and NH is deduced from various X-ray spectroscopies. In contrast, at higher N-content (5.0 at%) graphitic nitrogen was formed in which each N-atom trigonally bonds to three distinct sp2-hybridized carbons with substitution of the N-atoms for C atoms in the graphite layer. Upon nitrogen substitution, the total density of state close to Fermi level is increased to raise the valence-band maximum, as revealed by VB-PES spectra, indicating an electron donation from nitrogen, molecular bonding C/N/O coordination or/and lattice structure reorganization in GO:Nx. The well-ordered chemical environments induced by nitrogen dopant are revealed by XANES and RIXS measurements.

  15. Glow discharge optical emission spectroscopy: a complementary technique to analyze thin electrodeposited polyaniline films

    Energy Technology Data Exchange (ETDEWEB)

    Moutarlier, V. [Institut UTINAM, CNRS-UMR 6213, Université de Franche-Comté, 16 route de Gray, 25030 Besançon (France); Lakard, S., E-mail: sophie.lakard@univ-fcomte.fr [Institut UTINAM, CNRS-UMR 6213, Université de Franche-Comté, 16 route de Gray, 25030 Besançon (France); Patois, T. [Institute of Condensed Matter and Nanosciences, Université Catholique de Louvain, Croix du Sud, 1/4, 1348 Louvain-la-Neuve (Belgium); Lakard, B. [Institut UTINAM, CNRS-UMR 6213, Université de Franche-Comté, 16 route de Gray, 25030 Besançon (France)

    2014-01-01

    Glow Discharge Optical Emission Spectroscopy (GDOES) has been developed to perform depth profiles of thick metallic films, in tens of microns range. GDOES spectroscopy can also be used to analyze thin organic polymer films since this technique has a great potential thanks to its high depth resolution, multi-element capability, sensitivity, and adaptability to solids or films and to conducting or non-conducting samples. In particular thin electrodeposited conducting polymer films remain an unexplored field of investigation for GDOES technique. However GDOES was used in this work to analyze electrodeposited polyaniline films, in addition to other techniques such as profilometry, electron microscopy and X-ray diffraction (XRD). More precisely polyaniline thin films were electrodeposited from HCl solutions and the presence of an anilinium chloride excess at the top surface of the polymer film was demonstrated using GDOES and XRD. Rinsing of these films with water led to the removal of this excess and to the partial dedoping of the polymer film due to the porous structure of polymer films. Polyaniline thin films were also electrodeposited from H{sub 2}SO{sub 4} solutions and an anilinium hydrogen sulfate was similarly observed at the top surface of the polymer. This excess was removed by rinsing, contrary to hydrogen sulfate anions incorporated into the polymer film during the electrochemical polymerization that were not completely expulsed from the polyaniline films as proved using GDOES. - Highlights: • Polyaniline films were electrodeposited from HCl and H{sub 2}SO{sub 4} solutions • Polymer films were analyzed by Glow Discharge Optical Emission Spectroscopy (GDOES) • The incorporation of anions in the films was proved using GDOES depth profiles • The crystalline structure of polyaniline films was modified by water rinsing.

  16. 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.

  17. Extended calibration range for prompt photon emission in ion beam irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Bellini, F. [Dipartimento di Fisica, Sapienza Università di Roma, Roma (Italy); INFN Sezione di Roma, Roma (Italy); Boehlen, T.T.; Chin, M.P.W. [CERN, Geneva (Switzerland); Collamati, F. [Dipartimento di Fisica, Sapienza Università di Roma, Roma (Italy); INFN Sezione di Roma, Roma (Italy); De Lucia, E. [Laboratori Nazionali di Frascati dell' INFN, Frascati (Italy); Faccini, R., E-mail: riccardo.faccini@roma1.infn.it [Dipartimento di Fisica, Sapienza Università di Roma, Roma (Italy); INFN Sezione di Roma, Roma (Italy); Ferrari, A. [CERN, Geneva (Switzerland); Lanza, L. [Dipartimento di Fisica, Sapienza Università di Roma, Roma (Italy); INFN Sezione di Roma, Roma (Italy); Mancini-Terracciano, C. [CERN, Geneva (Switzerland); Dipartimento di Fisica, Università Roma Tre, Roma (Italy); Marafini, M. [Museo Storico della Fisica e Centro Studi e Ricerche “E. Fermi”, Roma (Italy); INFN Sezione di Roma, Roma (Italy); Mattei, I. [Dipartimento di Fisica, Università Roma Tre, Roma (Italy); Laboratori Nazionali di Frascati dell' INFN, Frascati (Italy); Morganti, S. [INFN Sezione di Roma, Roma (Italy); Ortega, P.G. [CERN, Geneva (Switzerland); Patera, V. [Dipartimento di Scienze di Base e Applicate per Ingegneria, Sapienza Università di Roma, Roma (Italy); INFN Sezione di Roma, Roma (Italy); Piersanti, L. [Dipartimento di Scienze di Base e Applicate per Ingegneria, Sapienza Università di Roma, Roma (Italy); Laboratori Nazionali di Frascati dell' INFN, Frascati (Italy); Russomando, A. [Center for Life Nano Science@Sapienza, Istituto Italiano di Tecnologia, Roma (Italy); INFN Sezione di Roma, Roma (Italy); Sala, P.R. [INFN Sezione di Milano, Milano (Italy); and others

    2014-05-01

    Monitoring the dose delivered during proton and carbon ion therapy is still a matter of research. Among the possible solutions, several exploit the measurement of the single photon emission from nuclear decays induced by the irradiation. To fully characterize such emission the detectors need development, since the energy spectrum spans the range above the MeV that is not traditionally used in medical applications. On the other hand, a deeper understanding of the reactions involving gamma production is needed in order to improve the physic models of Monte Carlo codes, relevant for an accurate prediction of the prompt-gamma energy spectrum. This paper describes a calibration technique tailored for the range of energy of interest and reanalyzes the data of the interaction of a 80 MeV/u fully stripped carbon ion beam with a Poly-methyl methacrylate target. By adopting the FLUKA simulation with the appropriate calibration and resolution a significant improvement in the agreement between data and simulation is reported.

  18. Extended calibration range for prompt photon emission in ion beam irradiation

    CERN Document Server

    Bellini, F.

    2014-01-01

    Monitoring the dose delivered during proton and carbon ion therapy is still a matter of research. Among the possible solutions, several exploit the measurement of the single photon emission from nuclear decays induced by the irradiation. To fully characterize such emission the detectors need development, since the energy spectrum spans the range above the MeV that is not traditionally used in medical applications. On the other hand, a deeper understanding of the reactions involving gamma production is needed in order to improve the physic models of Monte Carlo codes, relevant for an accurate prediction of the prompt-gamma energy spectrum.This paper describes a calibration technique tailored for the range of energy of interest and reanalyzes the data of the interaction of a 80MeV/u fully stripped carbon ion beam with a Poly-methyl methacrylate target. By adopting the FLUKA simulation with the appropriate calibration and resolution a significant improvement in the agreement between data and simulation is report...

  19. Fluorescence excitation-emission matrix spectroscopy of vitiligo skin in vivo (Conference Presentation)

    Science.gov (United States)

    Zhao, Jianhua; Richer, Vincent; Al Jasser, Mohammed; Zandi, Soodabeh; Kollias, Nikiforos; Kalia, Sunil; Zeng, Haishan; Lui, Harvey

    2016-02-01

    Fluorescence signals depend on the intensity of the exciting light, the absorption properties of the constituent molecules, and the efficiency with which the absorbed photons are converted to fluorescence emission. The optical features and appearance of vitiligo have been explained primarily on the basis of reduced epidermal pigmentation, which results in abnormal white patches on the skin. The objective of this study is to explore the fluorescence properties of vitiligo and its adjacent normal skin using fluorescence excitation-emission matrix (EEM) spectroscopy. Thirty five (35) volunteers with vitiligo were acquired using a double-grating spectrofluorometer with excitation and emission wavelengths of 260-450 nm and 300-700 nm respectively. As expected, the most pronounced difference between the spectra obtained from vitiligo lesions compared to normally pigmented skin was that the overall fluorescence was much higher in vitiligo; these differences increased at shorter wavelengths, thus matching the characteristic spectral absorption of epidermal melanin. When comparing the fluorescence spectra from vitiligo to normal skin we detected three distinct spectral bands centered at 280nm, 310nm, and 335nm. The 280nm band may possibly be related to inflammation, whereas the 335 nm band may arise from collagen or keratin cross links. The source of the 310 nm band is uncertain; it is interesting to note its proximity to the 311 nm UV lamps used for vitiligo phototherapy. These differences are accounted for not only by changes in epidermal pigment content, but also by other optically active cutaneous biomolecules.

  20. Emission Spectroscopy and Radiometric Measurements in the NASA Ames IHF Arc Jet Facility

    Science.gov (United States)

    Winter, Michael W.; Raiche, George A.; Prabhu, Dinesh K.

    2012-01-01

    Plasma diagnostic measurement campaigns in the NASA Ames Interaction Heating Facility (IHF) have been conducted over the last several years with a view towards characterizing the flow in the arc jet facility by providing data necessary for modeling and simulation. Optical emission spectroscopy has been used in the plenum and in the free jet of the nozzle. Radiation incident over a probe surface has also been measured using radiometry. Plenum measurements have shown distinct radial profiles of temperature over a range of operating conditions. For cases where large amounts of cold air are added radially to the main arc-heated stream, the temperature profiles are higher by as much as 1500 K than the profiles assumed in flow simulations. Optical measurements perpendicular to the flow direction in the free jet showed significant contributions to the molecule emission through inverse pre-dissociation, thus allowing determination of atom number densities from molecular emission. This has been preliminarily demonstrated with the N2 1st Positive System. Despite the use of older rate coefficients, the resulting atom densities are reasonable and surprisingly close to flow predictions.

  1. Intrinsic spontaneous emission-induced fluctuations of the output optical beam power and phase in a diode amplifier

    Science.gov (United States)

    Bogatov, A. P.; Drakin, A. E.; D'yachkov, N. V.; Gushchik, T. I.

    2016-08-01

    Output optical beam intensity and phase fluctuations are analysed in a classical approach to describing the propagation and amplification of spontaneous emission in the active region of a laser diode with a gain saturated by input monochromatic light. We find their spectral densities and dispersion and the correlation coefficient of the two-dimensional probability distribution function of the fluctuations.

  2. Time-resolved thermal lens spectroscopy with a single-pulsed laser excitation beam: an analytical model for dual-beam mode-mismatched experiments.

    Science.gov (United States)

    Sabaeian, Mohammad; Rezaei, Hamidreza; Ghalambor-Dezfouli, Abdolmohammad

    2017-02-01

    Pulsed laser beam excitations are more commonly used in thermal lens spectroscopy (TLS) than continuous-wave (CW) ones, because CW excitations limit the measurement to linear absorption processes [J. Opt. A5, 256 (2003)]. In this work, we present a new and full analytical model for a single-pulsed laser excitation dual-beam mode-mismatched TLS for low absorption solid-state and liquid samples. Our model has been based on a new solution of time-dependent heat equation for a finite-radius cylindrical sample exposed to a single-pulsed excitation laser beam. For low absorbent samples, unlike previous models, all aberration terms associated in the thermal lens were taken into account in Fresnel integration. Besides, the model provides a full analytical mathematical expression for the temperature rise, normalized signal intensity, and Z-scan photothermal lens signal. The model was confirmed with experimental data of distilled deionized water with excellent agreement. Therefore, the model allows us to extract thermo-optical properties of samples in an analytical and more accurate way.

  3. Emission Spectroscopy as a Probe into Photoinduced Intramolecular Electron Transfer in Polyazine Bridged Ru(II,Rh(III Supramolecular Complexes

    Directory of Open Access Journals (Sweden)

    Karen J. Brewer

    2010-08-01

    Full Text Available Steady-state and time-resolved emission spectroscopy are valuable tools to probe photochemical processes of metal-ligand, coordination complexes. Ru(II polyazine light absorbers are efficient light harvesters absorbing in the UV and visible with emissive 3MLCT excited states known to undergo excited state energy and electron transfer. Changes in emission intensity, energy or band-shape, as well as excited state lifetime, provide insight into excited state dynamics. Photophysical processes such as intramolecular electron transfer between electron donor and electron acceptor sub-units may be investigated using these methods. This review investigates the use of steady-state and time-resolved emission spectroscopy to measure excited state intramolecular electron transfer in polyazine bridged Ru(II,Rh(III supramolecular complexes. Intramolecular electron transfer in these systems provides for conversion of the emissive 3MLCT (metal-to-ligand charge transfer excited state to a non-emissive, but potentially photoreactive, 3MMCT (metal-to-metal charge transfer excited state. The details of the photophysics of Ru(II,Rh(III and Ru(II,Rh(III,Ru(II systems as probed by steady-state and time-resolved emission spectroscopy will be highlighted.

  4. Diagnostics of the ITER neutral beam test facility.

    Science.gov (United States)

    Pasqualotto, R; Serianni, G; Sonato, P; Agostini, M; Brombin, M; Croci, G; Dalla Palma, M; De Muri, M; Gazza, E; Gorini, G; Pomaro, N; Rizzolo, A; Spolaore, M; Zaniol, B

    2012-02-01

    The ITER heating neutral beam (HNB) injector, based on negative ions accelerated at 1 MV, will be tested and optimized in the SPIDER source and MITICA full injector prototypes, using a set of diagnostics not available on the ITER HNB. The RF source, where the H(-)∕D(-) production is enhanced by cesium evaporation, will be monitored with thermocouples, electrostatic probes, optical emission spectroscopy, cavity ring down, and laser absorption spectroscopy. The beam is analyzed by cooling water calorimetry, a short pulse instrumented calorimeter, beam emission spectroscopy, visible tomography, and neutron imaging. Design of the diagnostic systems is presented.

  5. Development of a Reference Database for Particle-Induced Gamma-ray Emission spectroscopy

    Science.gov (United States)

    Dimitriou, P.; Becker, H.-W.; Bogdanović-Radović, I.; Chiari, M.; Goncharov, A.; Jesus, A. P.; Kakuee, O.; Kiss, A. Z.; Lagoyannis, A.; Räisänen, J.; Strivay, D.; Zucchiatti, A.

    2016-03-01

    Particle-Induced Gamma-ray Emission (PIGE) is a powerful analytical technique that exploits the interactions of rapid charged particles with nuclei located near a sample surface to determine the composition and structure of the surface regions of solids by measurement of characteristic prompt γ rays. The potential for depth profiling of this technique has long been recognized, however, the implementation has been limited owing to insufficient knowledge of the physical data and lack of suitable user-friendly computer codes for the applications. Although a considerable body of published data exists in the nuclear physics literature for nuclear reaction cross sections with γ rays in the exit channel, there is no up-to-date, comprehensive compilation specifically dedicated to IBA applications. A number of PIGE cross-section data had already been uploaded to the Ion Beam Analysis Nuclear Data Library (IBANDL)

  6. A field programmable gate array-based time-resolved scaler for collinear laser spectroscopy with bunched radioactive potassium beams.

    Science.gov (United States)

    Rossi, D M; Minamisono, K; Barquest, B R; Bollen, G; Cooper, K; Davis, M; Hammerton, K; Hughes, M; Mantica, P F; Morrissey, D J; Ringle, R; Rodriguez, J A; Ryder, C A; Schwarz, S; Strum, R; Sumithrarachchi, C; Tarazona, D; Zhao, S

    2014-09-01

    A new data acquisition system including a Field Programmable Gate Array (FPGA) based time-resolved scaler was developed for laser-induced fluorescence and beam bunch coincidence measurements. The FPGA scaler was tested in a collinear laser-spectroscopy experiment on radioactive (37)K at the BEam COoler and LAser spectroscopy (BECOLA) facility at the National Superconducting Cyclotron Laboratory at Michigan State University. A 1.29 μs bunch width from the buncher and a bunch repetition rate of 2.5 Hz led to a background suppression factor of 3.1 × 10(5) in resonant photon detection measurements. The hyperfine structure of (37)K and its isotope shift relative to the stable (39)K were determined using 5 × 10(4) s(-1) (37)K ions injected into the BECOLA beam line. The obtained hyperfine coupling constants A((2)S(1/2)) = 120.3(1.4) MHz, A((2)P(1/2)) = 15.2(1.1) MHz, and A((2)P(3/2)) = 1.4(8) MHz, and the isotope shift δν(39, 37) = -264(3) MHz are consistent with the previously determined values, where available.

  7. A field programmable gate array-based time-resolved scaler for collinear laser spectroscopy with bunched radioactive potassium beams

    Science.gov (United States)

    Rossi, D. M.; Minamisono, K.; Barquest, B. R.; Bollen, G.; Cooper, K.; Davis, M.; Hammerton, K.; Hughes, M.; Mantica, P. F.; Morrissey, D. J.; Ringle, R.; Rodriguez, J. A.; Ryder, C. A.; Schwarz, S.; Strum, R.; Sumithrarachchi, C.; Tarazona, D.; Zhao, S.

    2014-09-01

    A new data acquisition system including a Field Programmable Gate Array (FPGA) based time-resolved scaler was developed for laser-induced fluorescence and beam bunch coincidence measurements. The FPGA scaler was tested in a collinear laser-spectroscopy experiment on radioactive 37K at the BEam COoler and LAser spectroscopy (BECOLA) facility at the National Superconducting Cyclotron Laboratory at Michigan State University. A 1.29 μs bunch width from the buncher and a bunch repetition rate of 2.5 Hz led to a background suppression factor of 3.1 × 105 in resonant photon detection measurements. The hyperfine structure of 37K and its isotope shift relative to the stable 39K were determined using 5 × 104 s-1 37K ions injected into the BECOLA beam line. The obtained hyperfine coupling constants A(2S1/2) = 120.3(1.4) MHz, A(2P1/2) = 15.2(1.1) MHz, and A(2P3/2) = 1.4(8) MHz, and the isotope shift δν39, 37 = -264(3) MHz are consistent with the previously determined values, where available.

  8. Experiments and FLUKA simulations of $^{12}C$ and $^{16}O$ beams for therapy monitoring by means of in-beam Positron Emission Tomography

    CERN Document Server

    Sommerer,; Ferrari, A

    2007-01-01

    Since 1997 at the experimental C-12 ion therapy facility at Gesellschaft fuer Schwerionenforschung (GSI), Darmstadt, Germany, more than 350 patients have been treated. The therapy is monitored with a dedicated positron emission tomograph, fully integrated into the treatment site. The measured beta+-activity arises from inelastic nuclear interactions between the beam particles an the nuclei of the patients tissue. Because the monitoring is done during the irradiation the method is called in-beam PET. The underlying principle of this monitoring is a comparison between the measured activity and a simulated one. The simulations are presently done by the PETSIM code which is dedicated to C-12 beams. In future ion therapy centers like the Heidelberger Ionenstrahl Therapiezentrum (HIT), Heidelberg, Germany, besides C-12 also proton, $^3$He and O-16 beams will be used for treatment and the therapy will be monitored by means of in-beam PET. Because PETSIM is not extendable to other ions in an easy way, a code capable ...

  9. Continuous measurements of volcanic gases from Popocatepetl volcano by thermal emission spectroscopy

    Science.gov (United States)

    Taquet, Noemie; Stremme, Wolfgang; Meza, Israel; Grutter, Michel

    2016-04-01

    Passive volcanic gas emissions have been poorly studied despite their impact on the atmospheric chemistry with important consequences on its geochemical cycles and climate change on regional and global scale. Therefore, long-term monitoring of volcanic gas plumes and their composition are of prime importance for climatic models and the estimation of the volcanic contribution to climate change. We present a new measurement and analysis strategy based on remote thermal emission spectroscopy which can provide continuous (day and night) information of the composition of the volcanic plume. In this study we show results from the Popocatepetl volcano in Mexico with measurements performed during the year 2015 from the Altzomoni Atmospheric Observatory (19.12N, -98.65W, 3,985 masl). This site, which forms part of the RUOA (www.ruoa.unam.mx) and NDACC (https://www2.acom.ucar.edu/irwg) networks, is located north of the crater of this active volcano at 12 km distance. Emission spectra were recorded with an FTIR spectrometer (OPAG22, Bruker) at 0.5 cm-1 spectral resolution and processed using the SFIT4 radiative transfer and profile retrieval code, based on the Optimal Estimation method (Rodgers, 1976; 1990; 2000). This newly improved methodology is intercompared to a former retrieval strategy using measurements from 2008 and recent results of the variability of the SiF4/SO2 composition ratio during 2015 is presented. A discussion of how the new measurements improve the understating of the impact of volcanic gas emissions on the atmosphere on global and regional scale is included.

  10. Asphaltene Erosion Process in Air Plasma: Emission Spectroscopy and Surface Analysis for Air-Plasma Reactions

    Institute of Scientific and Technical Information of China (English)

    H. MARTINEZ; O. FLORES; J. C. POVEDA; B. CAMPILLO

    2012-01-01

    Optical emission spectroscopy (OES) was applied for plasma characterization during the erosion of asphaltene substrates. An amount of 100 mg of asphaltene was carefully applied to an electrode and exposed to air-plasma glow discharge at a pressure of 1.0 Torr. The plasma was generated in a stainless steel discharge chamber by an ac generator at a frequency of 60 Hz, output power of 50 W and a gas flow rate of 1.8 L/min. The electron temperature and ion density were estimated to be 2.15±0.11 eV and (1.24±0.05)× 10^16 m^-3, respectively, using a double Langmuir probe. OES was employed to observe the emission from the asphaltene exposed to air plasma. Both molecular band emission from N2, N2+, OH, CH, NH, O2 as well as CN, and atomic light emission from V and Hγ were observed and used to monitor the evolution of asphaltene erosion. The asphaltene erosion was analyzed with the aid of a scanning electron microscope (SEM) equipped with an energy dispersive X-ray (EDX) detector. The EDX analysis showed that the time evolution of elements C, O, S and V were similar and the chemical composition of the exposed asphaltenes remained constant. Particle size evolution was measured, showing a maximum size of 2307 μm after 60 min. This behavior is most likely related to particle agglomeration as a function of time.

  11. Note: Ion-induced secondary electron emission from oxidized metal surfaces measured in a particle beam reactor

    Science.gov (United States)

    Marcak, Adrian; Corbella, Carles; de los Arcos, Teresa; von Keudell, Achim

    2015-10-01

    The secondary electron emission of metals induced by slow ions is characterized in a beam chamber by means of two coaxial semi-cylindrical electrodes with different apertures. The voltages of the outer electrode (screening), inner electrode (collector), and sample holder (target) were set independently in order to measure the effective yield of potential and kinetic electron emissions during ion bombardment. Aluminum samples were exposed to quantified beams of argon ions up to 2000 eV and to oxygen atoms and molecules in order to mimic the plasma-surface interactions on metallic targets during reactive sputtering. The variation of electron emission yield was correlated to the ion energy and to the oxidation state of Al surfaces. This system provides reliable measurements of the electron yields in real time and is of great utility to explore the fundamental surface processes during target poisoning occurring in reactive magnetron sputtering applications.

  12. Note: Ion-induced secondary electron emission from oxidized metal surfaces measured in a particle beam reactor

    Energy Technology Data Exchange (ETDEWEB)

    Marcak, Adrian; Corbella, Carles, E-mail: carles.corbella@rub.de; Keudell, Achim von [Research Group Reactive Plasmas, Ruhr-University Bochum, 44801 Bochum (Germany); Arcos, Teresa de los [Technical and Macromolecular Chemistry, Paderborn University, 33098 Paderborn (Germany)

    2015-10-15

    The secondary electron emission of metals induced by slow ions is characterized in a beam chamber by means of two coaxial semi-cylindrical electrodes with different apertures. The voltages of the outer electrode (screening), inner electrode (collector), and sample holder (target) were set independently in order to measure the effective yield of potential and kinetic electron emissions during ion bombardment. Aluminum samples were exposed to quantified beams of argon ions up to 2000 eV and to oxygen atoms and molecules in order to mimic the plasma-surface interactions on metallic targets during reactive sputtering. The variation of electron emission yield was correlated to the ion energy and to the oxidation state of Al surfaces. This system provides reliable measurements of the electron yields in real time and is of great utility to explore the fundamental surface processes during target poisoning occurring in reactive magnetron sputtering applications.

  13. Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Hellman, Hal

    1968-01-01

    This booklet discusses spectroscopy, the study of absorption of radiation by matter, including X-ray, gamma-ray, microwave, mass spectroscopy, as well as others. Spectroscopy has produced more fundamental information to the study of the detailed structure of matter than any other tools.

  14. Temperature Effect on the Optical Emission Intensity in Laser Induced Breakdown Spectroscopy of Super Alloys

    Science.gov (United States)

    Darbani, S. M. R.; Ghezelbash, M.; Majd, A. E.; Soltanolkotabi, M.; Saghafifar, H.

    2014-12-01

    In this paper, the influence of heating and cooling samples on the optical emission spectra and plasma parameters of laser-induced breakdown spectroscopy for Titanium 64, Inconel 718 super alloys, and Aluminum 6061 alloy is investigated. Samples are uniformly heated up to approximately 200°C and cooled down to -78°C by an external heater and liquid nitrogen, respectively. Variations of plasma parameters like electron temperature and electron density with sample temperature are determined by using Boltzmann plot and Stark broadening methods, respectively. Heating the samples improves LIBS signal strength and broadens the width of the spectrum. On the other hand, cooling alloys causes fluctuations in the LIBS signal and decrease it to some extent, and some of the spectral peaks diminish. In addition, our results show that electron temperature and electron density depend on the sample temperature variations.

  15. Plasma diagnostics in gas metal arc welding by optical emission spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Valensi, F; Pellerin, S; Zielinska, S [GREMI, Universite d' Orleans (Site de Bourges)/CNRS, BP 4043, 18028 Bourges cedex (France); Boutaghane, A [Universite des Sciences et de la Technologie Houari Boumediene, Alger (Algeria); Dzierzega, K [Marian Smoluchowski Institute of Physics, Jagellonian University, Krakow (Poland); Pellerin, N [CNRS, UPR3079 CEMHTI, 1D av. de la Recherche Scientifique, 45071 Orleans cedex 2 (France); Briand, F, E-mail: flavien.valensi@laplace.univ-tsle.f, E-mail: stephane.pellerin@univ-orleans.f, E-mail: aboutaghane@yahoo.f, E-mail: krzycho@netmail.if.uj.edu.p, E-mail: sylwia.zielinska@airliquide.co, E-mail: nadia.pellerin@univ-orleans.f, E-mail: francis.briand@airliquide.co [CTAS-Air Liquide Welding, Saint Ouen l' Aumone, 95315 Cergy-Pontoise cedex (France)

    2010-11-03

    The plasma column in a metal inert gas welding process is investigated by optical emission spectroscopy and high-speed imaging. The concentration and repartition of iron vapours are measured and correlated with the plasma and electrode geometric configuration. Plasma temperatures and electron densities are also measured for each studied position in the plasma. The temperatures are calculated using two different methods, allowing validation of the local thermodynamic equilibrium state of the plasma. The results show a maximum temperature of 12 500 K in the upper part of the arc, away from the arc axis. The iron concentration reaches a maximum of 0.3% close to the anode and strongly decreases along both the vertical and radial directions. The plasma thermophysical properties, calculated from this plasma composition, are then discussed regarding the metal transfer mode.

  16. Inductively coupled plasma optical emission spectroscopy determination of trace element composition of argan oil.

    Science.gov (United States)

    Gonzálvez, A; Ghanjaoui, M E; El Rhazi, M; de la Guardia, M

    2010-02-01

    A methodology based on inductively coupled plasma optical emission spectroscopy (ICP-OES) after microwave assisted acid digestion has been developed to determine the trace element content of Moroccan argan oil. Limit of detection values equal or lower than few mg/kg were obtained for all elements under study. To assure the accuracy of the whole procedure, recovery studies were carried out on argan oil samples spiked at different concentration levels from 10 to 200 µg/L. Quantitative average recovery values were obtained for all elements evaluated, demonstrating the suitability of this methodology for the determination of trace elements in argan oil samples. Aluminum, calcium, chromium, iron, potassium, lithium, magnesium, sodium, vanadium and zinc were quantitatively determined in Moroccan argan oils being found that their concentration is different of that found in other edible oils thus offering a way for authentication and for the evaluation of possible adulterations.

  17. In vivo neurochemistry with emission tomography and magnetic resonance spectroscopy: clinical applications.

    Science.gov (United States)

    Del Sole, Angelo; Gambini, Anna; Falini, Andrea; Lecchi, Michela; Lucignani, Giovanni

    2002-10-01

    The assessment of neurochemical processes in vivo has received much attention in the past decade as techniques such as positron or single photon emission tomography (PET and SPET), and magnetic resonance spectroscopy (MRS) have become more available. With PET and SPET, basic processes, such as blood flow and oxygen or glucose metabolism, can be regionally assessed, along with more specific functions such as the production, release, and reuptake of neurotransmitters and their occupancy of specific receptors. At the same time, MRS can reveal changes in concentration of several hydrogenate compounds in the brain. All these methods have been extensively applied for research in neurology, and some applications have reached the clinical level, namely for the study of degenerative diseases, motor-neuron diseases, movement disorders, cerebrovascular diseases, and epilepsy. This article focuses on the most relevant information that can be obtained with these complementary techniques to help clinicians in the assessment of neurological diseases.

  18. In vivo neurochemistry with emission tomography and magnetic resonance spectroscopy: clinical applications

    Energy Technology Data Exchange (ETDEWEB)

    Sole, Angelo Del [Azienda Ospedaliera San Paolo e Universita di Milano, 20142 Milan (Italy); Gambini, Anna; Falini, Andrea [IRCCS H San Raffaele e Universita Vita e Salute, 20132 Milan (Italy); Lecchi, Michela [Azienda Ospedaliera L. Sacco e Universita di Milano, 20157 Milan (Italy); Lucignani, Giovanni [Azienda Ospedaliera L. Sacco e Universita di Milano, 20157 Milan (Italy); Universita di Milano, Istituto di Scienze Radiologiche, Cattedra di Medicina Nucleare c/o Ospedale L. Sacco, Via G.B. Grassi, 74, 20157 Milan (Italy)

    2002-10-01

    The assessment of neurochemical processes in vivo has received much attention in the past decade as techniques such as positron or single photon emission tomography (PET and SPET), and magnetic resonance spectroscopy (MRS) have become more available. With PET and SPET, basic processes, such as blood flow and oxygen or glucose metabolism, can be regionally assessed, along with more specific functions such as the production, release, and reuptake of neurotransmitters and their occupancy of specific receptors. At the same time, MRS can reveal changes in concentration of several hydrogenate compounds in the brain. All these methods have been extensively applied for research in neurology, and some applications have reached the clinical level, namely for the study of degenerative diseases, motor-neuron diseases, movement disorders, cerebrovascular diseases, and epilepsy. This article focuses on the most relevant information that can be obtained with these complementary techniques to help clinicians in the assessment of neurological diseases. (orig.)

  19. Emission and propagation of Saturn kilometric radiation: Magnetoionic modes, beaming pattern, and polarization state

    Science.gov (United States)

    Lamy, L.; Cecconi, B.; Zarka, P.; Canu, P.; Schippers, P.; Kurth, W. S.; Mutel, R. L.; Gurnett, D. A.; Menietti, D.; Louarn, P.

    2011-04-01

    The Cassini mission crossed the source region of the Saturn kilometric radiation (SKR) on 17 October 2008. On this occasion, the Radio and Plasma Wave Science (RPWS) experiment detected both local and distant radio sources, while plasma parameters were measured in situ by the magnetometer and the Cassini Plasma Spectrometer. A goniopolarimetric inversion was applied to RPWS three-antenna electric measurements to determine the wave vector k and the complete state of polarization of detected waves. We identify broadband extraordinary (X) mode as well as narrowband ordinary (O) mode SKR at low frequencies. Within the source region, SKR is emitted just above the X mode cutoff frequency in a hot plasma, with a typical electron-to-wave energy conversion efficiency of ˜1% (2% peak). The knowledge of the k vector is then used to derive the locus of SKR sources in the kronian magnetosphere, which shows X and O components emanating from the same regions. We also compute the associated beaming angle at the source θ‧ = (k, -B) either from (1) in situ measurements or a model of the magnetic field vector (for local to distant sources) or (2) polarization measurements (for local sources). Obtained results, similar for both modes, suggest quasi-perpendicular emission for local sources, whereas the beaming pattern of distant sources appears as a hollow cone with a frequency-dependent constant aperture angle: θ‧ = 75° ± 15° below 300 kHz, decreasing at higher frequencies to reach θ‧ (1000 kHz) = 50° ± 25°. Finally, we investigate quantitatively the SKR polarization state, observed to be strongly elliptical at the source, and quasi-purely circular for sources located beyond approximately two kronian radii. We show that conditions of weak mode coupling are achieved along the raypath, under which the magnetoionic theory satisfactorily describes the evolution of the observed polarization. These results are analyzed comparatively with the auroral kilometric radiation at

  20. Comparative Studies on Effects of Acid Solutions on Aquatic Plants by Beam Deflection and Absorbance Spectroscopy Methods.

    Science.gov (United States)

    Wu, Xing-Zheng; Nie, Liangjiao; Inoue, Tomomi

    2015-01-01

    The beam deflection method and absorbance spectroscopy were applied to study effects of acid solutions on aquatic plants, and their results were compared. Aquatic plants Egeria densa and Ceratophyllum demersum L were used as model plants. In absorbance experiments, a piece of the plants was put in a beaker with 20 mL HCl solution, and absorbance of the HCl solution was measured every 30 min. In beam deflection experiments, a probe beam from a He-Ne laser was focused to a vicinity of the plants in a culture dish with HCl solution by an objective lens, and deflection signals of the probe beam were monitored by a position sensor. Absorbance spectra of the HCl solutions with immersing of the plants showed absorbance below 410 nm, suggesting that some compounds leaked from the plants into the HCl solutions. Changes of absorbance and deflection signals with immersion time were examined for different pH levels. The changing trends of the absorbance and deflection signals with time were similar, but the absorbance changes were delayed for about 2 - 3 h. The absorbance method could not detect the effect of the pH 5.0 HCl solutions on the aquatic plants, while the deflection method could.

  1. Spectroscopy

    CERN Document Server

    Walker, S

    1976-01-01

    The three volumes of Spectroscopy constitute the one comprehensive text available on the principles, practice and applications of spectroscopy. By giving full accounts of those spectroscopic techniques only recently introduced into student courses - such as Mössbauer spectroscopy and photoelectron spectroscopy - in addition to those techniques long recognised as being essential in chemistry teaching - sucha as e.s.r. and infrared spectroscopy - the book caters for the complete requirements of undergraduate students and at the same time provides a sound introduction to special topics for graduate students.

  2. Oxidation of nanostructured Ti films produced by low energy cluster beam deposition: An X-ray Photoelectron Spectroscopy characterization

    Energy Technology Data Exchange (ETDEWEB)

    Simone, Monica de, E-mail: desimone@tasc.infm.it [CNR-IOM Laboratorio TASC, Area Science Park Basovizza, 34149 Trieste (Italy); Snidero, Elena [CNR-IOM Laboratorio TASC, Area Science Park Basovizza, 34149 Trieste (Italy); Coreno, Marcello [CNR-IMIP, c/o Laboratorio TASC Area Science Park Basovizza, 34149 Trieste (Italy); Sincrotrone Trieste ScpA, Area Science Park Basovizza, 34149 Trieste (Italy); Bongiorno, Gero [Fondazione Filarete, v.le Ortles 22/4, 20139 Milano (Italy); Giorgetti, Luca [Istituto Europeo di Oncologia, Dip. di Oncologia Sperimentale, Via Adamello 16, 20139, Milano (Italy); Amati, Matteo [Sincrotrone Trieste ScpA, Area Science Park Basovizza, 34149 Trieste (Italy); Cepek, Cinzia [CNR-IOM Laboratorio TASC, Area Science Park Basovizza, 34149 Trieste (Italy)

    2012-05-01

    We used in-situ X-ray Photoelectron Spectroscopy (XPS) to study the oxidation process of a cluster-assembled metallic titanium film exposed to molecular oxygen at room temperature. The nanostructured film has been grown on a Si(111) substrate, in ultra high vacuum conditions, by coupling a supersonic cluster beam deposition system with an XPS experimental chamber. Our results show that upon in-situ oxygen exposure Ti{sup 3+} is the first oxidation state observed, followed by Ti{sup 4+}, whereas Ti{sup 2+} is practically absent during the whole process. Our results compare well with the existing literature on Ti films produced using other techniques.

  3. Invited Article: The coherent optical laser beam recombination technique (COLBERT) spectrometer: Coherent multidimensional spectroscopy made easier

    Science.gov (United States)

    Turner, Daniel B.; Stone, Katherine W.; Gundogdu, Kenan; Nelson, Keith A.

    2011-08-01

    We have developed an efficient spectrometer capable of performing a wide variety of coherent multidimensional measurements at optical wavelengths. The two major components of the largely automated device are a spatial beam shaper which controls the beam geometry and a spatiotemporal pulse shaper which controls the temporal waveform of the femtosecond pulse in each beam. We describe how to construct, calibrate, and operate the device, and we discuss its limitations. We use the exciton states of a semiconductor nanostructure as a working example. A series of complex multidimensional spectra—displayed in amplitude and real parts—reveals increasingly intricate correlations among the excitons.

  4. LZIFU: an emission-line fitting toolkit for integral field spectroscopy data

    Science.gov (United States)

    Ho, I.-Ting; Medling, Anne M.; Groves, Brent; Rich, Jeffrey A.; Rupke, David S. N.; Hampton, Elise; Kewley, Lisa J.; Bland-Hawthorn, Joss; Croom, Scott M.; Richards, Samuel; Schaefer, Adam L.; Sharp, Rob; Sweet, Sarah M.

    2016-09-01

    We present lzifu (LaZy-IFU), an idl toolkit for fitting multiple emission lines simultaneously in integral field spectroscopy (IFS) data. lzifu is useful for the investigation of the dynamical, physical and chemical properties of gas in galaxies. lzifu has already been applied to many world-class IFS instruments and large IFS surveys, including the Wide Field Spectrograph, the new Multi Unit Spectroscopic Explorer (MUSE), the Calar Alto Legacy Integral Field Area (CALIFA) survey, the Sydney-Australian-astronomical-observatory Multi-object Integral-field spectrograph (SAMI) Galaxy Survey. Here we describe in detail the structure of the toolkit, and how the line fluxes and flux uncertainties are determined, including the possibility of having multiple distinct kinematic components. We quantify the performance of lzifu, demonstrating its accuracy and robustness. We also show examples of applying lzifu to CALIFA and SAMI data to construct emission line and kinematic maps, and investigate complex, skewed line profiles presented in IFS data. The code is made available to the astronomy community through github. lzifu will be further developed over time to other IFS instruments, and to provide even more accurate line and uncertainty estimates.

  5. Updated Spitzer emission spectroscopy of bright transiting hot Jupiter HD 189733b

    Energy Technology Data Exchange (ETDEWEB)

    Todorov, Kamen O. [Department of Astronomy and Astrophysics, The Pennsylvania State University, University Park, PA 16802 (United States); Deming, Drake [Department of Astronomy, University of Maryland at College Park, College Park, MD 20742 (United States); Burrows, Adam [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States); Grillmair, Carl J., E-mail: todorovk@phys.ethz.ch [Spitzer Science Center, California Institute of Technology, Mail Stop 220-6, Pasadena, CA 91125 (United States)

    2014-12-01

    We analyze all existing secondary eclipse time series spectroscopy of hot Jupiter HD 189733b acquired with the now defunct Spitzer/Infrared Spectrograph (IRS) instrument. We describe the novel approaches we develop to remove the systematic effects and extract accurate secondary eclipse depths as a function of wavelength in order to construct the emission spectrum of the exoplanet. We compare our results with a previous study by Grillmair et al. that did not examine all data sets available to us. We are able to confirm the detection of a water feature near 6 μm claimed by Grillmair et al. We compare the planetary emission spectrum to three model families—based on isothermal atmosphere, gray atmosphere, and two realizations of the complex radiative transfer model by Burrows et al., adopted in Grillmair et al.'s study. While we are able to reject the simple isothermal and gray models based on the data at the 97% level just from the IRS data, these rejections hinge on eclipses measured within a relatively narrow wavelength range, between 5.5 and 7 μm. This underscores the need for observational studies with broad wavelength coverage and high spectral resolution, in order to obtain robust information on exoplanet atmospheres.

  6. Metastable argon atom density in complex argon/acetylene plasmas determined by means of optical absorption and emission spectroscopy

    Science.gov (United States)

    Sushkov, Vladimir; Herrendorf, Ann-Pierra; Hippler, Rainer

    2016-10-01

    Optical emission and absorption spectroscopy has been utilized to investigate the instability of acetylene-containing dusty plasmas induced by growing nano-particles. The density of Ar(1s5) metastable atoms was derived by two methods: tunable diode laser absorption spectroscopy and with the help of the branching ratio method of emitted spectral lines. Results of the two techniques agree well with each other. The density of Ar(1s3) metastable atoms was also measured by means of optical emission spectroscopy. The observed growth instability leads to pronounced temporal variations of the metastable and other excited state densities. An analysis of optical line ratios provides evidence for a depletion of free electrons during the growth cycle but no indication for electron temperature variations.

  7. X-ray emission spectroscopy study of the Verwey transition in Fe sub 3 O sub 4

    CERN Document Server

    Moewes, A; Finkelstein, L D; Galakhov, A V; Gota, S; Gautier-Soyer, M; Rueff, J P; Hague, C F

    2003-01-01

    The temperature-dependent Verwey transition in a 500 A (111) thin film of Fe sub 3 O sub 4 (magnetite) has been studied using soft-x-ray emission spectroscopy at room temperature and below the transition temperature T sub V. The Fe L sub 2 sub , sub 3 x-ray emission spectra show an increase in the intensity of the L sub 2 emission relative to the L sub 3 emission below T sub V. This is independent of the excitation energy and is attributed to a metal-insulator transition across T sub V. Comparison of the Fe L sub 3 emission and O K alpha spectra with LDA band structure calculations supports the suggestion of charge ordering in Fe sub 3 O sub 4 at low temperature.

  8. Atom-specific look at the surface chemical bond using x-ray emission spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Nilsson, A.; Wassdahl, N.; Weinelt, M. [Uppsala Univ. (Sweden)] [and others

    1997-04-01

    CO and N{sub 2} adsorbed on the late transition metals have become prototype systems regarding the general understanding of molecular adsorption. It is in general assumed that the bonding of molecules to transition metals can be explained in terms of the interaction of the frontier HOMO and LUMO molecular orbitals with the d-orbitals. In such a picture the other molecular orbitals should remain essentially the same as in the free molecule. For the adsorption of the isoelectronic molecules CO and N{sub 2} this has led to the so called Blyholder model i.e., a synergetic {sigma} (HOMO) donor and {pi} (LUMO) backdonation bond. The authors results at the ALS show that such a picture is oversimplified. The direct observation and identification of the states related to the surface chemical bond is an experimental challenge. For noble and transition metal surfaces, the adsorption induced states overlap with the metal d valence band. Their signature is therefore often obscured by bulk substrate states. This complication has made it difficult for techniques such as photoemission and inverse photoemission to provide reliable information on the energy of chemisorption induced states and has left questions unanswered regarding the validity of the frontier orbitals concept. Here the authors show how x-ray emission spectroscopy (XES), in spite of its inherent bulk sensitivity, can be used to investigate adsorbed molecules. Due to the localization of the core-excited intermediate state, XE spectroscopy allows an atomic specific separation of the valence electronic states. Thus the molecular contributions to the surface measurements make it possible to determine the symmetry of the molecular states, i.e., the separation of {pi} and {sigma} type states. In all the authors can obtain an atomic view of the electronic states involved in the formation of the chemical bond to the surface.

  9. Terahertz Desorption Emission Spectroscopy (THz DES) - ‘ALMA in the Lab’

    Science.gov (United States)

    Emile Auriacombe, Olivier Bruno Jacques; Fraser, Helen; Ellison, Brian; Ioppolo, Sergio; Rea, Simon

    2016-06-01

    ALMA is revolutionising our scope to identify and locate molecules that have been desorbed from ices, particularly complex organic molecules (COMS), which provide a vital link between interstellar and prebiotic chemistry. Explaining the existence of these molecules in star-forming regions relies on an empirical understanding of the chemistry that underpins their formation:- do COMS form predominantly in the solid-phase and then desorb to the gas phase, or do only “smaller” species, radials or ions desorb and then undergo gas-phase chemical reactions to generate larger COMS?-are the rotational state populations in COMS only attributable to equilibrium chemistry, or could their formation mechanisms and desorption processes affect the rotational state occupancy of these molecules, thereby directly tying certain species to solid-state origins?We have developed a novel laboratory method - THz Desorption Emission Spectroscopy (THz-DES) that combines “traditional” laboratory astrophysics high-vacuum ice experiments with a sensitive high-spectral-resolution terahertz total-power heterodyne radiometer 1,2, partially mirroring the spectral range of ALMA band 7 (275- 373 GHz). Ices are grown in situ on a cold-plate, situated in a vacuum cell, then (thermally) desorbed. The sub-mm emission spectra of the resultant gas-phase molecules are detected as a function of time, temperature, or distance from the surface. Our first THz DES results will be shown for pure and binary ice systems including H2O, N2O and CH3OH. They show good correlation with established methods e.g. TPD, with the advantage of exploiting the molecular spectroscopy to unravel surface dynamics, state-occupancy, and unequivocal molecular identification, as well as concurrently measuring desorption barriers and molecular yields. We will extend our technique to a broader frequency range, enabling us to detect radical and ion desorption, to differentiate between A and E populations of CH3OH or ortho

  10. Unreported Emission Lines of Rb, Ce, La, Sr, Y, Zr, Pb and Se Detected Using Laser-Induced Breakdown Spectroscopy

    Science.gov (United States)

    Lepore, K. H.; Mackie, J.; Dyar, M. D.; Fassett, C. I.

    2017-01-01

    Information on emission lines for major and minor elements is readily available from the National Institute of Standards and Technology (NIST) as part of the Atomic Spectra Database. However, tabulated emission lines are scarce for some minor elements and the wavelength ranges presented on the NIST database are limited to those included in existing studies. Previous work concerning minor element calibration curves measured using laser-induced break-down spectroscopy found evidence of Zn emission lines that were not documented on the NIST database. In this study, rock powders were doped with Rb, Ce, La, Sr, Y, Zr, Pb and Se in concentrations ranging from 10 percent to 10 parts per million. The difference between normalized spectra collected on samples containing 10 percent dopant and those containing only 10 parts per million were used to identify all emission lines that can be detected using LIBS (Laser-Induced Breakdown Spectroscopy) in a ChemCam-like configuration at the Mount Holyoke College LIBS facility. These emission spectra provide evidence of many previously undocumented emission lines for the elements measured here.

  11. Prediction of methane emission from lactating dairy cows using milk fatty acids and mid-infrared spectroscopy.

    Science.gov (United States)

    van Gastelen, Sanne; Dijkstra, Jan

    2016-09-01

    Enteric methane (CH4 ) production is among the main targets of greenhouse gas mitigation practices for the dairy industry. A simple, robust and inexpensive measurement technique applicable on a large scale to estimate CH4 emission from dairy cattle would therefore be valuable. Milk fatty acids (MFA) are related to CH4 production because of the common biochemical pathway between CH4 and fatty acids in the rumen. A summary of studies that investigated the predictive power of MFA composition for CH4 emission indicated good potential, with predictive power ranging between 47% and 95%. Until recently, gas chromatography (GC) was the principal method used to determine the MFA profile, but GC is unsuitable for routine analysis. This has led to the application of mid-infrared (MIR) spectroscopy. The major advantages of using MIR spectroscopy to predict CH4 emission include its simplicity and potential practical application at large scale. Disadvantages include the inability to predict important MFA for CH4 prediction, and the moderate predictive power for CH4 emission. It may not be sufficient to predict CH4 emission based on MIR alone. Integration with other factors, like feed intake, nutrient composition of the feed, parity, and lactation stage may improve the prediction of CH4 emission using MIR spectra. © 2016 Society of Chemical Industry.

  12. Determination of total tin in canned food using inductively coupled plasma atomic emission spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Perring, Loic; Basic-Dvorzak, Marija [Department of Quality and Safety Assurance, Nestle Research Centre, P.O. Box 44, Vers chez-les-Blanc, 1000, Lausanne (Switzerland)

    2002-09-01

    Tin is considered to be a priority contaminant by the Codex Alimentarius Commission. Tin can enter foods either from natural sources, environmental pollution, packaging material or pesticides. Higher concentrations are found in processed food and canned foods. Dissolution of the tinplate depends on the of food matrix, acidity, presence of oxidising reagents (anthocyanin, nitrate, iron and copper) presence of air (oxygen) in the headspace, time and storage temperature. To reduce corrosion and dissolution of tin, nowadays cans are usually lacquered, which gives a marked reduction of tin migration into the food product. Due to the lack of modern validated published methods for food products, an ICP-AES (Inductively coupled plasma-atomic emission spectroscopy) method has been developed and evaluated. This technique is available in many laboratories in the food industry and is more sensitive than atomic absorption. Conditions of sample preparation and spectroscopic parameters for tin measurement by axial ICP-AES were investigated for their ruggedness. Two methods of preparation involving high-pressure ashing or microwave digestion in volumetric flasks were evaluated. They gave complete recovery of tin with similar accuracy and precision. Recoveries of tin from spiked products with two levels of tin were in the range 99{+-}5%. Robust relative repeatabilities and intermediate reproducibilities were <5% for different food matrices containing >30 mg/kg of tin. Internal standard correction (indium or strontium) did not improve the method performance. Three emission lines for tin were tested (189.927, 283.998 and 235.485 nm) but only 189.927 nm was found to be robust enough with respect to interferences, especially at low tin concentrations. The LOQ (limit of quantification) was around 0.8 mg/kg at 189.927 nm. A survey of tin content in a range of canned foods is given. (orig.)

  13. DETECTION OF REST-FRAME OPTICAL LINES FROM X-SHOOTER SPECTROSCOPY OF WEAK EMISSION-LINE QUASARS

    Energy Technology Data Exchange (ETDEWEB)

    Plotkin, Richard M.; Gallo, Elena [Department of Astronomy, University of Michigan, 1085 South University Avenue, Ann Arbor, MI 48109 (United States); Shemmer, Ohad [Department of Physics, University of North Texas, Denton, TX 76203 (United States); Trakhtenbrot, Benny [Institute for Astronomy, Department of Physics, ETH Zurich, Wolfgang-Pauli-Strasse 27, CH-8093 Zurich (Switzerland); Anderson, Scott F. [Department of Astronomy, University of Washington, Box 351580, Seattle, WA 98195 (United States); Brandt, W. N.; Luo, Bin; Schneider, Donald P. [Department of Astronomy and Astrophysics, 525 Davey Lab, The Pennsylvania State University, University Park, PA 16802 (United States); Fan, Xiaohui [Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States); Lira, Paulina [Departamento de Astronomia, Universidad de Chile, Camino del Observatorio 1515, Santiago (Chile); Richards, Gordon T. [Department of Physics, Drexel University, 3141 Chestnut Street, Philadelphia, PA 19104 (United States); Strauss, Michael A. [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States); Wu, Jianfeng, E-mail: rplotkin@umich.edu [Harvard-Smithsonian Center for Astrophysics, MS 6, 60 Garden Street Cambridge, MA 02138 (United States)

    2015-06-01

    Over the past 15 yr, examples of exotic radio-quiet quasars with intrinsically weak or absent broad emission line regions (BELRs) have emerged from large-scale spectroscopic sky surveys. Here, we present spectroscopy of seven such weak emission line quasars (WLQs) at moderate redshifts (z = 1.4–1.7) using the X-shooter spectrograph, which provides simultaneous optical and near-infrared spectroscopy covering the rest-frame ultraviolet (UV) through optical. These new observations effectively double the number of WLQs with spectroscopy in the optical rest-frame, and they allow us to compare the strengths of (weak) high-ionization emission lines (e.g., C iv) to low-ionization lines (e.g., Mg ii, Hβ, Hα) in individual objects. We detect broad Hβ and Hα emission in all objects, and these lines are generally toward the weaker end of the distribution expected for typical quasars (e.g., Hβ has rest-frame equivalent widths ranging from 15–40 Å). However, these low-ionization lines are not exceptionally weak, as is the case for high-ionization lines in WLQs. The X-shooter spectra also display relatively strong optical Fe ii emission, Hβ FWHM ≲ 4000 km s{sup −1}, and significant C iv blueshifts (≈1000–5500 km s{sup −1}) relative to the systemic redshift; two spectra also show elevated UV Fe ii emission, and an outflowing component to their (weak) Mg ii emission lines. These properties suggest that WLQs are exotic versions of “wind-dominated” quasars. Their BELRs either have unusual high-ionization components, or their BELRs are in an atypical photoionization state because of an unusually soft continuum.

  14. Pair production and γ ray emission in collisions of e+e-beams

    Science.gov (United States)

    Del Gaudio, Fabrizio; Grismayer, Thomas; Fonseca, Ricardo; Mori, Warren; Silva, Luis

    2016-10-01

    The fast development in Plasma Wakefield Acceleration suggests that high quality relativistic electron/positron beams, having tens of GeV in energy and densities up to 10cm-3, can be delivered by tabletop devices in the near future. With these parameters, the collective electromagnetic field of one beam compares to the Schwinger field in the boosted frame of the oncoming beam, thus the quantum regime is approached where particles are capable to emit hard photons apt to decay in electron positron pairs. Under certain conditions, additionally to quantum effects, the disruption effect takes place altering the beams density profile more or less severely. Estimates regarding beams energy loss and the number of pairs generated in such collisions were addressed by P. Chen with simplified beam geometry. We present a model for the low disruption regime, with realistic beams parameters, that predicts the average radiation intensity, its spectrum and the number of pairs created during the beam-beam interaction. Our model agrees with fully consistent PIC simulations done with the QED module of OSIRIS 3.0. The results obtained qualify this setup as possible γ ray source and show that relevant number of pairs, higher than previous estimates, is produced at these beam energies and densities.

  15. Study of Nuclear Moments and Mean Square Charge Radii by Collinear Fast-Beam Laser Spectroscopy

    CERN Multimedia

    2002-01-01

    The collinear fast-beam laser technique is used to measure atomic hyperfine structures and isotope shifts of unstable nuclides produced at ISOLDE. This gives access to basic nuclear ground-state and isomeric-state properties such as spins, magnetic dipole and electric quadrupole moments, and the variation of the nuclear mean square charge radius within a sequence of isotopes. \\\\ \\\\ Among the various techniques used for this purpose, the present approach is of greatest versatility, due to the direct use of the beams from the isotope separator. Their phase-space properties are exploited to achieve high sensitivity and resolution. The optical spectra of neutral atoms are made accessible by converting the ion beams into fast atomic beams. This is accomplished in the charge-exchange cell which is kept at variable potential ($\\pm$10~kV) for Doppler-tuning of the effective laser wavelength. The basic optical resolution of 10$^{-8}$ requires a 10$^{-5}$ stability of the 60~kV main acceleration voltage and low energy ...

  16. The relationship between visible light emission and species fraction of the hydrogen ion beams extracted from 2.45 GHz microwave discharge

    CERN Document Server

    Cortázar, O D; Tarvainen, O; Kalvas, T; Koivisto, H

    2015-01-01

    The relationship between Balmer-α and Fulcher-band emissions with extracted H +, H+2 , and H+3 ions is demonstrated for a 2.45 GHz microwave discharge. Ion mass spectra and optical measurements of Balmer-α and Fulcher-band emissions have been obtained with a Wien Filter having an optical view-port on the plasma chamber axis. The beam of approximately 1 mA is analyzed for different plasma conditions simultaneously with the measurement of light emissions both with temporal resolution. The use of visible light emissions as a valuable diagnostic tool for monitoring the species fraction of the extracted beams is proposed.

  17. Ultra-nonlocality in density functional theory for photo-emission spectroscopy.

    Science.gov (United States)

    Uimonen, A-M; Stefanucci, G; van Leeuwen, R

    2014-05-14

    We derive an exact expression for the photocurrent of photo-emission spectroscopy using time-dependent current density functional theory (TDCDFT). This expression is given as an integral over the Kohn-Sham spectral function renormalized by effective potentials that depend on the exchange-correlation kernel of current density functional theory. We analyze in detail the physical content of this expression by making a connection between the density-functional expression and the diagrammatic expansion of the photocurrent within many-body perturbation theory. We further demonstrate that the density functional expression does not provide us with information on the kinetic energy distribution of the photo-electrons. Such information can, in principle, be obtained from TDCDFT by exactly modeling the experiment in which the photocurrent is split into energy contributions by means of an external electromagnetic field outside the sample, as is done in standard detectors. We find, however, that this procedure produces very nonlocal correlations between the exchange-correlation fields in the sample and the detector.

  18. Trace cobalt speciation in bacteria and at enzymic active sites using emission Moessbauer spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Kamnev, A.A.; Antonyuk, L.P.; Smirnova, V.E.; Serebrennikova, O.B. [Laboratory of Biochemistry, Institute of Biochemistry and Physiology of Plants and Microorganisms, Russian Academy of Sciences, Saratov (Russian Federation); Kulikov, L.A.; Perfiliev, Yu.D. [Laboratory of Nuclear Chemistry Techniques, Department of Radiochemistry, Faculty of Chemistry, Moscow State University (Russian Federation)

    2002-02-01

    {sup 57}Co emission Moessbauer spectroscopy (EMS) allows the chemical state of cobalt, as influenced by its coordination environment, to be monitored in biological samples at its physiological (trace) concentrations. To draw attention to EMS as a valuable tool for speciation of cobalt in biocomplexes, the process of cobalt(II) metabolism in cells of the plant growth-promoting rhizobacterium Azospirillum brasilense Sp245 was investigated using EMS of {sup 57}Co{sup II}-doped bacterial cells. EMS measurements also showed {sup 57}Co{sup II}-activated glutamine synthetase (GS, a key enzyme of nitrogen metabolism, isolated from this bacterium) to have two different cobalt(II) forms at its active sites, in agreement with data available on other bacterial GSs. Chemical after-effects following electron capture by the nucleus of the parent {sup 57}Co{sup II} during the {sup 57}Co{yields}{sup 57}Fe transition, which contribute to the formation of a stabilised daughter {sup 57}Fe{sup III} component along with the nucleogenic {sup 57}Fe{sup II} forms, are also briefly considered. (orig.)

  19. Observation of iron spin-states using tabletop x-ray emission spectroscopy and microcalorimeter sensors

    Science.gov (United States)

    Joe, Y. I.; O'Neil, G. C.; Miaja-Avila, L.; Fowler, J. W.; Jimenez, R.; Silverman, K. L.; Swetz, D. S.; Ullom, J. N.

    2016-01-01

    X-ray emission spectroscopy (XES) is a powerful probe of the electronic and chemical state of elemental species embedded within complex compounds. X-ray sensors that combine high resolving power and high collecting efficiency are desirable for photon-starved XES experiments such as measurements of dilute, gaseous, and radiation-sensitive samples, time-resolved measurements, and in-laboratory XES. To assess whether arrays of cryogenic microcalorimeters will be useful in photon-starved XES scenarios, we demonstrate that these emerging energy-dispersive sensors can detect the spin-state of 3d electrons of iron in two different compounds, Fe2O3 and FeS2. The measurements were conducted with a picosecond pulsed laser-driven plasma as the exciting x-ray source. The use of this tabletop source suggests that time-resolved in-laboratory XES will be possible in the future. We also present simulations of {{K}}α and {{K}}β spectra that reveal the spin-state sensitivity of different combinations of sensor resolution and accumulated counts. These simulations predict that our current experimental apparatus can perform time-resolved XES measurements on some samples with a measurement time of a few 10 s of hours per time delay.

  20. Dynamics of Bloch State Positronium Emission from MOF Targets Studied via Rydberg TOF Spectroscopy

    Science.gov (United States)

    Piñeiro Escalera, Alina; Jones, Adric; Mills, Allen

    2016-05-01

    Recent advances in the efficient production and detection of Rydberg positronium (Ps) have made it possible to perform energy- and angle- resolved time-of-flight (TOF) spectroscopy with Ps. We report here TOF measurements of Ps emission from the metal-oxide framework (MOF) targets, MOF-5 and ZIF-8. MOFs are a recently synthesized class of chemical structures, characterized by high long-range order and large surface area to volume ratios (i.e., they are highly porous and uniform, crystalline materials). Ps is found to be emitted predominantly in a series of monoenergetic peaks, providing clear evidence of Ps Bloch states. Measuring the relative populations of the monoenergetic peaks, as a function of implantation energy and target temperature, provides insight into the target-dependent dynamics of Bloch state Ps. Work supported by the U.S. National Science Foundation Grants No. PHY 1206100 and No. PHY 1040590 and the National Science Foundation Graduate Research Fellowship Progam (NSF-GRFP). DOE BES DE-FG02-13ER46972 (MOF-5 synthesis and characterization).

  1. Assessment of diabetic neuropathy with emission tomography and magnetic resonance spectroscopy.

    Science.gov (United States)

    Rao, Harshvardhan; Gaur, Neeraj; Tipre, Dnyanesh

    2017-04-01

    Diabetic neuropathies (DNs) are nerve-damaging disorders associated with diabetes. They are commonly attributed to peripheral nerves and primarily affect the limbs of the patient. They cause altered sensitivity to external stimuli along with loss in balance and reflexes of the affected patient. DNs are associated with a variety of clinical manifestations including autonomic failure and are caused by poor management of blood sugar levels. Imaging modalities provide vital information about early physiological changes in DNs. This review summarizes contributions by various teams of scientists in developing imaging methods to assess physiological changes in DNs and ongoing clinical trials where imaging modalities are applied to evaluate therapeutic intervention in DNs. Development of PET, single photon emission computed tomography, and magnetic resonance spectroscopy methods over the past 20 years are reviewed in the diagnostic assessment of DNs. Abnormal radiotracer pharmacokinetics and neurometabolite spectra in affected organs confirm physiological abnormalities in DN. With the use of the Siemens Biograph mMR and GE Signa - 60 cm (PET/MRI scanner), simultaneous acquisition of physiological and anatomical information could enhance understanding of DNs and accelerate drug development.

  2. Spectroscopy

    DEFF Research Database (Denmark)

    Berg, Rolf W.

    This introductory booklet covers the basics of molecular spectroscopy, infrared and Raman methods, instrumental considerations, symmetry analysis of molecules, group theory and selection rules, as well as assignments of fundamental vibrational modes in molecules.......This introductory booklet covers the basics of molecular spectroscopy, infrared and Raman methods, instrumental considerations, symmetry analysis of molecules, group theory and selection rules, as well as assignments of fundamental vibrational modes in molecules....

  3. Time-resolved measurement of emission profiles in pulsed radiofrequency glow discharge optical emission spectroscopy: Investigation of the pre-peak

    Energy Technology Data Exchange (ETDEWEB)

    Alberts, D. [Department of Physical and Analytical Chemistry, Faculty of Chemistry, University of Oviedo, Julian Claveria 8, 33006 Oviedo (Spain); Horvath, P. [Swiss Federal Laboratories for Materials Testing and Research (EMPA), Feuerwerkerstrasse 39, 3602 Thun (Switzerland); Nelis, Th. [LAPLACE, Universite Paul Sabatier, 118 rte de Narbonne, Bat3R2, 31062 Toulouse Cedex (France); CU Jean Francois Champollion, Place de Verdun 81012 Albi Cedex 9 (France); Pereiro, R. [Department of Physical and Analytical Chemistry, Faculty of Chemistry, University of Oviedo, Julian Claveria 8, 33006 Oviedo (Spain); Bordel, N. [Department of Physics, Faculty of Science, University of Oviedo, Calvo Sotelo, 33007 Oviedo (Spain); Michler, J. [Swiss Federal Laboratories for Materials Testing and Research (EMPA), Feuerwerkerstrasse 39, 3602 Thun (Switzerland); Sanz-Medel, A., E-mail: asm@uniovi.e [Department of Physical and Analytical Chemistry, Faculty of Chemistry, University of Oviedo, Julian Claveria 8, 33006 Oviedo (Spain)

    2010-07-15

    Radiofrequency glow discharge coupled to optical emission spectroscopy has been used in pulsed mode in order to perform a detailed study of the measured temporal emission profiles for a wide range of copper transitions. Special attention has been paid to the early emission peak (or so-called pre-peak), observed at the beginning of the emission pulse profile. The effects of the important pulse parameters such as frequency, duty cycle, pulse width and power-off time, have been studied upon the Cu pulse emission profiles. The influence of discharge parameters, such as pressure and power, was studied as well. Results have shown that the intensity observed in the pre-peak can be 10 times as large as the plateau value for resonant lines and up to 5 times in case of transitions to the metastable levels. Increasing pressure or power increased the pre-peak intensity while its appearance in time changed. The pre-peak decreased when the discharge off-time was shorter than 100 {mu}s. According to such results, the presence of the pre-peak could be probably due to the lack of self-absorption during the first 50 {mu}s, and not to the ignition of the plasma. Under the selected operation conditions, the use of the pre-peak emission as analytical signals increases the linearity of calibration curves for resonant lines subjected to self-absorption at high concentrations.

  4. In-beam gamma-ray spectroscopy of 35Mg and 33Na

    CERN Document Server

    Gade, A; Brown, B A; Campbell, C M; Cook, J M; Ettenauer, S; Glasmacher, T; Kemper, K W; McDaniel, S; Obertelli, A; Otsuka, T; Ratkiewicz, A; Terry, J R; Utsuno, Y; Weisshaar, D

    2011-01-01

    Excited states in the very neutron-rich nuclei 35Mg and 33Na were populated in the fragmentation of a 38Si projectile beam on a Be target at 83 MeV/u beam energy. We report on the first observation of gamma-ray transitions in 35Mg, the odd-N neighbor of 34Mg and 36Mg, which are known to be part of the "Island of Inversion" around N = 20. The results are discussed in the framework of large- scale shell-model calculations. For the A = 3Z nucleus 33Na, a new gamma-ray transition was observed that is suggested to complete the gamma-ray cascade 7/2+ --> 5/2+ --> 3/2+ gs connecting three neutron 2p-2h intruder states that are predicted to form a close-to-ideal K = 3/2 rotational band in the strong-coupling limit.

  5. Analysis of the fine structure of Sn$^{11+...14+}$ ions by optical spectroscopy in an electron beam ion trap

    CERN Document Server

    Windberger, A; Borschevsky, A; Ryabtsev, A; Dobrodey, S; Bekker, H; Eliav, E; Kaldor, U; Ubachs, W; Hoekstra, R; López-Urrutia, J R Crespo; Versolato, O O

    2016-01-01

    We experimentally re-evaluate the fine structure of Sn$^{11+...14+}$ ions. These ions are essential in bright extreme-ultraviolet (EUV) plasma-light sources for next-generation nanolithography, but their complex electronic structure is an open challenge for both theory and experiment. We combine optical spectroscopy of magnetic dipole $M1$ transitions, in a wavelength range covering 260\\,nm to 780\\,nm, with charge-state selective ionization in an electron beam ion trap. Our measurements confirm the predictive power of \\emph{ab initio} calculations based on Fock space coupled cluster theory. We validate our line identification using semi-empirical Cowan calculations with adjustable wavefunction parameters. Available Ritz combinations further strengthen our analysis. Comparison with previous work suggests that line identifications in the EUV need to be revisited.

  6. A Chemical Detector for Gas Chromatography Using Pulsed Discharge Emission Spectroscopy on a Microchip

    Science.gov (United States)

    Luo, X.; Zhu, W.; Mitra, B.; Liu, J.; Liu, T.; Fan, X.; Gianchandani, Y.

    2011-12-01

    There is increasing interest in miniaturized systems for chemical analysis in harsh environments. Chemical detection by emission spectroscopy of on-chip microdischarges [1-3] can be performed at >200°C [4], suggesting utility inspace exploration, volcanic monitoring, and oil well monitoring. This abstract describes the first use of pulsed microdischarge spectroscopy for gas chromatography (GC).This effort supports NASA interests in monitoring closed-loop life support systems for spacecraft. The microdischarge occurs on a 1cm2 glass chip (Fig. 1a), with thin-film Ni electrodes separated by 160μm. A glass lid with a grooved gas-flow channel, and inlet/outlet capillary tubes are epoxy-sealed to the chip. Located downstream of the 1.7m-long, RTX-1-coated, GC separation column, the microdischarge chip is read by a spectrometer. In a typical experiment (Fig. 1b), a mixture of acetone 3.6μg, 1-hexanol 2.8μg and nitrobenzene 3.0μg, is injected, with He carrier gas at 1.56sccm, through the GC. Acetone elutes quickly while nitrobenzene is slower. Microdischarges are triggered at 0.5Hz for 6 min., and 0.04Hz thereafter. Each microdischarge consumes ≈8mJ; the average power is ≈1.14mW. The spectrum (Fig. 1b, inset) shows that the 388nm peak, representing CN/CH fragments [5], is enhanced by carbon compounds. Its strength relative to the 588nm peak of He provides a chromatogram. Fig. 1b also shows a benchmark result from a commercial flame ionization detector (FID). The differences in elution time are attributed to differences in the gas flow paths for the two detectors [1]. REFERENCES [1] Eijkel et al, Anal. Chem, 2000 [2] Mitra et al, IEEE Trans Plasma Sci, 2008 [3] Mitra et al, IEEE Sensors, 2008 [4] Wright et al, APL, 2009 [5] Pearse et al, The Identification of Molecular Spectra, 1963

  7. Measurements of methane emissions from landfills using mobile plume method with trace gas and cavity ring-down spectroscopy

    Science.gov (United States)

    Mønster, J.; Kjeldsen, P.; Scheutz, C.

    2012-04-01

    Methane is emitted to the atmosphere from both anthropogenic and natural sources. One of the major anthropogenic sources is methane produced by bacteria in anaerobic environments such as rice pads and landfills. Land filling has for many years been the preferred waste disposal method, resulting in a large methane production with a large contribution to the global increase in atmospheric green house gas concentration. Several steps have been taken to reduce the emission of methane from landfills. In order to validate the effect of these steps, a measurement method is needed to quantify methane emissions with a large spatial variation. One method is to use a highly sensitive and fast analytical method, capable of measuring the atmospheric concentration methane downwind from emission areas. Combined with down-wind measurements of a trace gas, emitted at a controlled mass flow rate, the methane emission can be calculated. This method is called the mobile plume method, as the whole plume is measured by doing several transects. In the current study a methane/acetylene analyzer with cavity ring-down spectroscopy detection (Picarro, G2203) was used to estimate methane from a number of Danish landfills. We measured at both active and closed landfills and investigated the difference in methane emission. At landfills where the emissions could have more than one origin, the source strength of the different emission areas was determined by accurate trace gas positioning and choosing appropriate wind speed and measurement distance. To choose these factors, we addressed the uncertainties and limitations of the method with respect to the configuration of the trace gas bottles and the distance between the emission area and the measurement points. Composting of organic material in large piles was done at several of the investigated landfills and where possible, the methane emission from this partly anaerobic digestion was measured as a separate emission.

  8. Investigations of the cathode region of an argon arc plasma by degenerate four-wave mixing laser spectroscopy and optical emission spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Dzierzega, K [Marian Smoluchowski Institute of Physics, Jagiellonian University, ul. Reymonta 4, 30-059 Cracow (Poland); Pokrzywka, B [Mt. Suhora Observatory, Cracow Pedagogical University, ul. Podchorazych 2, 30-083 Cracow (Poland); Pellerin, S [LASEP, Universite d' Orleans-Centre Universitaire de Bourges, Rue Gaston Berger BP 4043, 18028 Bourges (France)

    2004-07-07

    Degenerate four-wave mixing (DFWM) laser spectroscopy was used in local studies of atmospheric pressure argon plasma generated in a free-burning arc. The results of plasma diagnostics using the DFWM method were compared to the results obtained with optical emission measurements. In the cathode region of the arc the maxima of both the DFWM signal and the emission coefficient for the 696.5 nm Ar I line depend on the distance from the cathode tip. This effect proves the departure of the plasma state from local thermal equilibrium (LTE) as it has been reported by many authors. On the other hand the Stark shifts of the 696.5 nm Ar I line determined by the DFWM method in relation to plasma diagnostic results show no deviations from LTE on the arc axis down to 1.0 mm from the cathode tip.

  9. Soft X-ray emission spectroscopy of liquids and lithium batterymaterials

    Energy Technology Data Exchange (ETDEWEB)

    Augustsson, Andreas [Uppsala Univ. (Sweden)

    2004-01-01

    Lithium ion insertion into electrode materials is commonly used in rechargeable battery technology. The insertion implies changes in both the crystal structure and the electronic structure of the electrode material. Side-reactions may occur on the surface of the electrode which is exposed to the electrolyte and form a solid electrolyte interface (SEI). The understanding of these processes is of great importance for improving battery performance. The chemical and physical properties of water and alcohols are complicated by the presence of strong hydrogen bonding. Various experimental techniques have been used to study geometrical structures and different models have been proposed to view the details of how these liquids are geometrically organized by hydrogen bonding. However, very little is known about the electronic structure of these liquids, mainly due to the lack of suitable experimental tools. In this thesis examples of studies of lithium battery electrodes and liquid systems using soft x-ray emission spectroscopy will be presented. Monochromatized synchrotron radiation has been used to accomplish selective excitation, in terms of energy and polarization. The electronic structure of graphite electrodes has been studied, before and after lithium intercalation. Changes in the electronic structure upon lithiation due to transfer of electrons into the graphite π-bands have been observed. Transfer of electrons in to the 3d states of transition metal oxides upon lithiation have been studied, through low energy excitations as dd- and charge transfer-excitations. A SEI was detected on cycled graphite electrodes. By the use of selective excitation different carbon sites were probed in the SEI. The local electronic structure of water, methanol and mixtures of the two have been examined using a special liquid cell, to separate the liquid from the vacuum in the experimental chamber. Results from the study of liquid water showed a strong influence on the 3a1 molecular

  10. Multi-epoch Spectroscopy of Dwarf Galaxies with AGN Signatures: Identifying Sources with Persistent Broad Hα Emission

    Science.gov (United States)

    Baldassare, Vivienne F.; Reines, Amy E.; Gallo, Elena; Greene, Jenny E.; Graur, Or; Geha, Marla; Hainline, Kevin; Carroll, Christopher M.; Hickox, Ryan C.

    2016-09-01

    We use time-domain optical spectroscopy to distinguish between broad emission lines powered by accreting black holes (BHs) and stellar processes (i.e., supernovae) for 16 galaxies identified as active galactic nucleus (AGN) candidates by Reines et al (2013). Our study is primarily focused on those objects with narrow emission line ratios dominated by star formation, for which the origin of the broad Hα emission was unclear. Based on follow-up spectroscopy, we find that the broad Hα emission has faded or was ambiguous for all of the star-forming objects (14/16), over baselines ranging from 5-14 years, suggesting a transient stellar process was responsible for the broad emission in previous Sloan Digital Sky Survey observations. For the two objects in our follow-up sample with narrow-line AGN signatures (RGG 9 and RGG 119), we find persistent broad Hα emission consistent with an AGN origin. Additionally, we use high spectral resolution observations to measure stellar velocity dispersions for 15 objects in the Reines et al. (2013) sample, all with narrow-line ratios indicating the presence of an AGN. Stellar masses range from ˜ 5× {10}8 to 3× {10}9 M ⊙, and we measure {σ }* in the range of 28{--}71 {km} {{{s}}}-1. These {σ }* correspond to some of the lowest-mass galaxies with optical signatures of AGN activity. We show that RGG 119, the one object that has both a measured {σ }* and persistent broad Hα emission, falls near the extrapolation of the {\\text{}}{M}{BH}-{σ }\\star relation to the low-mass end.

  11. Fast timing with plastic scintillators for in-beam heavy-ion spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Hoischen, R., E-mail: robert.hoischen@nuclear.lu.se [Department of Physics, Lund University, SE-22100 Lund (Sweden); GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, D-64291 Darmstadt (Germany); Pietri, S. [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, D-64291 Darmstadt (Germany); Rudolph, D. [Department of Physics, Lund University, SE-22100 Lund (Sweden); Prokopowicz, W.; Schaffner, H. [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, D-64291 Darmstadt (Germany); Emde, S. [Lehrstuhl fuer Operations Management, Friedrich-Schiller-Universitaet Jena, D-07743 Jena (Germany); Golubev, P. [Department of Physics, Lund University, SE-22100 Lund (Sweden); Wendt, A. [Institut fuer Kernphysik, Universitaet zu Koeln, D-50937 Koeln (Germany); Kurz, N.; Wollersheim, H.J.; Gerl, J. [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, D-64291 Darmstadt (Germany)

    2011-10-21

    The design, R and D, and testing of a new plastic-scintillator detector for Time-of-Flight measurements with relativistic heavy-ion beams are presented. A design approach using 32 independent precise timing measurements of the same physical event is followed. This is different from the conventional scheme, which aims at two or four high-precision measurements. A circular, 27 cm in diameter, BC-420 plastic-scintillator sheet is read-out by 32 photomultiplier tubes in order to achieve an intrinsic detector resolution on the order of 10 ps root mean square.

  12. Automatic laser beam alignment using blob detection for an environment monitoring spectroscopy

    Science.gov (United States)

    Khidir, Jarjees; Chen, Youhua; Anderson, Gary

    2013-05-01

    This paper describes a fully automated system to align an infra-red laser beam with a small retro-reflector over a wide range of distances. The component development and test were especially used for an open-path spectrometer gas detection system. Using blob detection under OpenCV library, an automatic alignment algorithm was designed to achieve fast and accurate target detection in a complex background environment. Test results are presented to show that the proposed algorithm has been successfully applied to various target distances and environment conditions.

  13. High resolution acoustic measurement system and beam pattern reconstruction method for bat echolocation emissions.

    Science.gov (United States)

    Gaudette, Jason E; Kloepper, Laura N; Warnecke, Michaela; Simmons, James A

    2014-01-01

    Measurements of the transmit beam patterns emitted by echolocating bats have previously been limited to cross-sectional planes or averaged over multiple signals using sparse microphone arrays. To date, no high-resolution measurements of individual bat transmit beams have been reported in the literature. Recent studies indicate that bats may change the time-frequency structure of their calls depending on the task, and suggest that their beam patterns are more dynamic than previously thought. To investigate beam pattern dynamics in a variety of bat species, a high-density reconfigurable microphone array was designed and constructed using low-cost ultrasonic microphones and custom electronic circuitry. The planar array is 1.83 m wide by 1.42 m tall with microphones positioned on a 2.54 cm square grid. The system can capture up to 228 channels simultaneously at a 500 kHz sampling rate. Beam patterns are reconstructed in azimuth, elevation, and frequency for visualization and further analysis. Validation of the array measurement system and post-processing functions is shown by reconstructing the beam pattern of a transducer with a fixed circular aperture and comparing the result with a theoretical model. To demonstrate the system in use, transmit beam patterns of the big brown bat, Eptesicus fuscus, are shown.

  14. Characterization of a direct dc-excited discharge in water by optical emission spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Bruggeman, Peter; Leys, Christophe [Department of Applied Physics, Ghent University, Jozef Plateaustraat 22, B-9000 Ghent (Belgium); Schram, Daan [Department of Applied Physics, Technische Universiteit Eindhoven, PO Box 513, 5600 MB Eindhoven (Netherlands); Gonzalez, Manuel A [Departamento de Fisica Aplicada, Universidad de Valladolid, 47011 Valladolid (Spain); Rego, Robby [Flemish Institute of Technological Research, VITO Materials, Boeretang 200, B-2400 Mol (Belgium); Kong, Michael G [Department of Electronic and Electrical Engineering, Loughborough University, Loughborough, Leicestershire LE11 3TU (United Kingdom)], E-mail: peter.bruggeman@ugent.be

    2009-05-01

    Dc-excited discharges generated in water at the tip of a tungsten wire which is located at the orifice of a quartz capillary are investigated by time-averaged optical emission spectroscopy. Two distinctive discharge modes are observed. For small conductivities of the liquid the discharge is a streamer-like discharge in the liquid itself (liquid mode). For conductivities above typically 45 {mu}S cm{sup -1} a large vapour bubble is formed and a streamer discharge in this vapour bubble is observed (bubble mode). Plasma temperatures and electron densities are investigated for both modes. The gas temperature is estimated from the rotational temperature of N{sub 2}(C-B) and is 1600 {+-} 200 K for the bubble mode and 1900 {+-} 200 K for the liquid mode. The rotational temperature of OH(A-X) is up to 2 times larger and cannot be used as an estimate for the gas temperature. The rotational population distribution of OH(A), {nu} = 0 is also non-Boltzmann with a large overpopulation of high rotational states. This discrepancy in rotational temperatures is discussed in detail. Electron densities are obtained from the Stark broadening of the hydrogen Balmer beta line. The electron densities in the liquid mode are of the order of 10{sup 21} m{sup -3}. In the bubble mode electron densities are significantly smaller: (3-4) x 10{sup 20} m{sup -3}. These values are compared with the Stark broadening of the hydrogen alpha and gamma lines and with electron densities obtained from current density measurements. The chemical reactivities of the bubble and liquid modes are compared by means of the hydrogen peroxide production rate.

  15. Optical emission spectroscopy diagnostics of an atmospheric pressure direct current microplasma jet

    Energy Technology Data Exchange (ETDEWEB)

    Sismanoglu, B.N., E-mail: bogos@ita.b [Departamento de Fisica, Instituto Tecnologico de Aeronautica, Comando-Geral de Tecnologia Aeroespacial, Pca Marechal Eduardo Gomes 50, 12 228-900, Sao Jose dos Campos, SP (Brazil); Amorim, J., E-mail: jayr.amorim@bioetanol.org.b [Centro de Ciencia e Tecnologia do Bioetanol - CTBE, Caixa Postal 6170, 13083-970 Campinas, Sao Paulo (Brazil); Souza-Correa, J.A., E-mail: jorge.correa@bioetanol.org.b [Centro de Ciencia e Tecnologia do Bioetanol - CTBE, Caixa Postal 6170, 13083-970 Campinas, Sao Paulo (Brazil); Oliveira, C., E-mail: carlosf@ita.b [Departamento de Fisica, Instituto Tecnologico de Aeronautica, Comando-Geral de Tecnologia Aeroespacial, Pca Marechal Eduardo Gomes 50, 12 228-900, Sao Jose dos Campos, SP (Brazil); Gomes, M.P., E-mail: gomesmp@ita.b [Departamento de Fisica, Instituto Tecnologico de Aeronautica, Comando-Geral de Tecnologia Aeroespacial, Pca Marechal Eduardo Gomes 50, 12 228-900, Sao Jose dos Campos, SP (Brazil)

    2009-11-15

    This paper is about the use of optical emission spectroscopy as a diagnostic tool to determine the gas discharge parameters of a direct current (98% Ar-2% H{sub 2}) non-thermal microplasma jet, operated at atmospheric pressure. The electrical and optical behaviors were studied to characterize this glow discharge. The microplasma jet was investigated in the normal and abnormal glow regimes, for current ranging from 10 to 130 mA, at approx 220 V of applied voltage for copper cathode. OH (A {sup 2}SIGMA{sup +}, nu = 0 -> X {sup 2}PI, nu' = 0) rotational bands at 306.357 nm and also the 603.213 nm Ar I line, which is sensitive to van der Waals broadening, were used to determine the gas temperature, which ranges from 550 to 800 K. The electron number densities, ranging from 6.0 x 10{sup 14} to 1.4 x 10{sup 15} cm{sup -3}, were determined through a careful analysis of the main broadening mechanisms of the H{sub beta} line. From both 603.213 nm and 565.070 nm Ar I line broadenings, it was possible to obtain simultaneously electron number density and temperature (approx 8000 K). Excitation temperatures were also measured from two methods: from two Cu I lines and from Boltzmann-plot of 4p-4s and 5p-4s Ar I transitions. By employing H{sub alpha} line, the hydrogen atoms' H temperature was estimated (approx 18,000 K) and found to be surprisingly hotter than the excitation temperature.

  16. Proton magnetic resonance spectroscopy and single photon emission CT in patients with olivopontocerebellar atrophy

    Energy Technology Data Exchange (ETDEWEB)

    Ikuta, Naomi [Yamaguchi Univ., Ube (Japan). School of Medicine

    1998-04-01

    Using proton magnetic resonance spectroscopy ({sup 1}H-MRS) and single photon emission CT (SPECT), the cerebellum of patients with olivopontocerebellar atrophy (OPCA) and of age-matched control subjects was studied. A spectrum was collected from a 27 cm{sup 3} (3 x 3 x 3 cm) voxel in the cerebellum containing white and gray matters in order to measure the distribution and relative signal intensities of N-acetylaspartate (NAA), creatine (Cre) and choline (Cho). In the cerebellum of the patients with OPCA, mean NAA/Cre ratios for OPCA patients were significantly decreased compared with normal control subjects (OPCA, 1.01{+-}0.247; controls, 1.526{+-}0.144: p<0.001). Mean NAA/Cho ratios for OPCA patients were slightly decreased (OPCA, 1.285{+-}0.228; controls 1.702{+-}0.469: p<0.06). Cho/Cre ratios valued in the cerebellum of OPCA patients were not significantly different from those in normal controls (OPCA, 0.793{+-}0.186; controls, 0.946{+-}0.219). The ratio of RI count in the cerebellum to that in the occipital lobe was significantly decreased in OPCA patients (OPCA, 0.947{+-}0.096; controls, 1.06{+-}0.063: p<0.01). Cerebellar signs were assessed including gait ataxia, limb ataxia, dysarthria, saccadic pursuit, and nystagmus separately or in combination. In patients with more severe ataxic gait and dysarthria, MRS revealed slightly lowered NAA/Cre ratio. There was no significant correlation between NAA/Cre ratio and severity of other clinical signs. The MRS and SPECT findings give a confirmative evidence of hypofunction in cerebellum of patients with OPCA. (author)

  17. Characterization of a high current pulsed arc using optical emission spectroscopy

    Science.gov (United States)

    Sousa Martins, R.; Zaepffel, C.; Chemartin, L.; Lalande, Ph; Soufiani, A.

    2016-10-01

    In this paper, we present the investigation realized on an experimental setup that simulates an arc column subjected to the transient phase of a lightning current waveform in laboratory conditions. Optical emission spectroscopy is employed to assess space- and time-resolved properties of this high current pulsed arc. Different current peak levels are utilised in this work, ranging from 10 kA to 100 kA, with a peak time around 15 µs. Ionic lines of nitrogen and oxygen are used to determine the radial profiles of temperature and electron density of the arc channel over time from 2 µs to 36 µs. A combination of 192 N II and O II lines is considered in the calculation of the bound-bound contribution of the absorption coefficient of the plasma channel. Calculations of the optical thickness showed that self-absorption of these ionic lines in the arc column is important. To obtain temperature and electron density profiles in the arc, we solved the radiative transfer equation across the channel under an axisymmetric assumption and considering the channel formed by uniform concentric layers. For the 100 kA current peak level, the temperature reaches more than 38 000 K and the electron density reaches 5  ×  1018 cm-3. The pressure inside the channel is calculated using the air plasma composition at local thermodynamic equilibrium, and reaches 45 bar. The results are discussed and utilised to estimate the electrical conductivity of the arc channel.

  18. Spectroscopy of high lying resonances in 9Be produced with radioactive 8Li beams

    Directory of Open Access Journals (Sweden)

    Lépine-Szily A.

    2014-04-01

    Full Text Available We present the results of the 8Li(p,α5He and 8Li(p,p8Li reactions measured at the RIBRAS (Radioactive Ion Beams in Brazil system. The experiment was realized in inverse kinematics using a thick [CH2]n polyethylene target and an incident 8Li beam, produced by RIBRAS. Using the thick target method, the complete excitation function could be measured between Ecm = 0.2 − 2.1 MeV, which includes the Gamow peak energy region. The excitation function of the 8Li(p,α5He reaction, populating resonances between 16.888 and 19.0 MeV in 9Be, was obtained[1] and the resonances were fitted using R-matrix calculations. This study shed light on spins, parities, partial widths and isospin values of high lying resonances in 9Be. The measurement of the resonant elastic scattering 8Li(p,p8Li populating resonances in the same energy region can constrain the resonance parameters. Preliminary results of the elastic scattering are also presented.

  19. Spectroscopy of high lying resonances in {sup 9}Be produced with radioactive {sup 8}Li beams

    Energy Technology Data Exchange (ETDEWEB)

    Lepini-Szily, A.; Leistenschneider, E.; Lichtenthäler, R.; Guimaraes, V.; Condori, R. Pampa; Scarduelli, V.; Rossi, E.; Zagatto, V.A.; Aguiar, V.A.P.; Duarte, J., E-mail: alinka@if.usp.br [Universidade de Sao Paulo (USP), Sao Paulo, SP (Brazil). Instituto de Fisica; Mendes Junior, D.R.; Faria, P.N. de; Santos, H. [Universidade Federal Fluminense (UFF), Niteroi, RJ (Brazil). Instituto de Fisica; Descouvemont, P. [Physique Nucleaire Theorique et Physique Mathematique, Universite Libre de Bruxelles (ULB), Brussels (Belgium); Barioni, A. [Universidade Federal da Bahia (UFBA), Salvador, BA (Brazil); Pires, K.C.C. [Universidade Tecnologica Federal do Parana (UFTPR), Cornelio Procopio, PR (Brazil); Morcelle, V. [Universidade Federal de Itajuba (UNIFEI), Itabira, MG (Brazil); Moraes, M.C. [Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil); Britos, T.; Assuncao, M. [Universidade Federal de Sao Paulo (UNIFESP), Diadema, SP (Brazil); Zamora, J.C. [Technische Universität Darmstadt, (Germany); Shorto, J.M.B. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2014-07-01

    We present the results of the {sup 8}Li(p,α){sup 5}He and {sup 8}Li(p,p){sup 8}Li reactions measured at the RIBRAS (Radioactive Ion Beams in Brazil) system. The experiment was realized in inverse kinematics using a thick [CH{sub 2}]{sub n} polyethylene target and an incident {sup 8}Li beam, produced by RIBRAS. Using the thick target method, the complete excitation function could be measured between E{sub cm} = 0.2 - 2.1 MeV, which includes the Gamow peak energy region. The excitation function of the {sup 8}Li(p,α){sup 5}He reaction, populating resonances between 16.888 and 19.0 MeV in {sup 9}Be, was obtained[1] and the resonances were fitted using R-matrix calculations. This study shed light on spins, parities, partial widths and isospin values of high lying resonances in {sup 9}Be. The measurement of the resonant elastic scattering {sup 8}Li(p,p){sup 8}Li populating resonances in the same energy region can constrain the resonance parameters. Preliminary results of the elastic scattering are also presented. (author)

  20. Avalanche dynamics of structural phase transitions in shape memory alloys by acoustic emission spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Ludwig, Benno

    2009-09-24

    In this work the avalanche dynamics of five shape memory samples has been analyzed by acoustic emission spectroscopy. The acoustic emission spectroscopy is particularly suitable for this analysis as it couples with high sensitivity to small structural changes caused by nucleation processes, interface movements, or variant rearrangements [91]. Owing to its high time resolution it provides a statistical approach to describe the jerky and intermittent character of the avalanche dynamics [20]. Rate-dependent cooling and heating runs have been conducted in order to study time-dependent aspects of the transition dynamics of the single crystals Ni{sub 63}Al{sub 37}, Au{sub 50.5}Cd{sub 49.5}, and Fe{sub 68.8}Pd{sup single}{sub 31.2}, and the polycrystalline sample Fe{sub 68.8}Pd{sup poly}{sub 31.2}. Moreover, a ferromagnetic Ni{sub 52}Mn{sub 23}Ga{sub 25} single crystal has been studied by temperature cycles under an applied magnetic field and additionally by magnetic-field cycles at a constant temperature in the martensitic phase. All samples analyzed in this work show power law behavior in the acoustic emission features amplitude, energy, and duration, which indicates scale-free behavior. The access to these power law spectra allows an investigation of energy barriers separating the metastable states, which give rise to avalanche transition dynamics. By performing rate-dependent experiments the importance of thermal fluctuations and the impact of martensite respectively twin stabilization processes have been examined. In the case of the Ni{sub 52}Mn{sub 23}Ga{sub 25} sample, the magnetic-field-induced variant rearrangement at slow field cycles leads to stronger signals than the rearrangement at quick cycles. This behavior can be explained by twin stabilization processes, which are accompanied by a reduction of the twin boundary mobility. For Ni{sub 63}Al{sub 37}, the combination of relevant thermal fluctuations, different involved time scales, and a high degree of

  1. Avalanche dynamics of structural phase transitions in shape memory alloys by acoustic emission spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Ludwig, Benno

    2009-09-24

    In this work the avalanche dynamics of five shape memory samples has been analyzed by acoustic emission spectroscopy. The acoustic emission spectroscopy is particularly suitable for this analysis as it couples with high sensitivity to small structural changes caused by nucleation processes, interface movements, or variant rearrangements [91]. Owing to its high time resolution it provides a statistical approach to describe the jerky and intermittent character of the avalanche dynamics [20]. Rate-dependent cooling and heating runs have been conducted in order to study time-dependent aspects of the transition dynamics of the single crystals Ni{sub 63}Al{sub 37}, Au{sub 50.5}Cd{sub 49.5}, and Fe{sub 68.8}Pd{sup single}{sub 31.2}, and the polycrystalline sample Fe{sub 68.8}Pd{sup poly}{sub 31.2}. Moreover, a ferromagnetic Ni{sub 52}Mn{sub 23}Ga{sub 25} single crystal has been studied by temperature cycles under an applied magnetic field and additionally by magnetic-field cycles at a constant temperature in the martensitic phase. All samples analyzed in this work show power law behavior in the acoustic emission features amplitude, energy, and duration, which indicates scale-free behavior. The access to these power law spectra allows an investigation of energy barriers separating the metastable states, which give rise to avalanche transition dynamics. By performing rate-dependent experiments the importance of thermal fluctuations and the impact of martensite respectively twin stabilization processes have been examined. In the case of the Ni{sub 52}Mn{sub 23}Ga{sub 25} sample, the magnetic-field-induced variant rearrangement at slow field cycles leads to stronger signals than the rearrangement at quick cycles. This behavior can be explained by twin stabilization processes, which are accompanied by a reduction of the twin boundary mobility. For Ni{sub 63}Al{sub 37}, the combination of relevant thermal fluctuations, different involved time scales, and a high degree of

  2. Development of Advanced Electrochemical Emission Spectroscopy for Monitoring Corrosion in Simulated DOE Liquid Waste

    Energy Technology Data Exchange (ETDEWEB)

    Digby D. Macdonald; Brian M. Marx; Sejin Ahn; Julio de Ruiz; Balaji Soundararaja; Morgan Smith; and Wendy Coulson

    2008-01-15

    Various forms of general and localized corrosion represent principal threats to the integrity of DOE liquid waste storage tanks. These tanks, which are of a single wall or double wall design, depending upon their age, are fabricated from welded carbon steel and contain a complex waste-form comprised of NaOH and NaNO{sub 3}, along with trace amounts of phosphate, sulfate, carbonate, and chloride. Because waste leakage can have a profound environmental impact, considerable interest exists in predicting the accumulation of corrosion damage, so as to more effectively schedule maintenance and repair. The different tasks that are being carried out under the current program are as follows: (1) Theoretical and experimental assessment of general corrosion of iron/steel in borate buffer solutions by using electrochemical impedance spectroscopy (EIS), ellipsometry and XPS techniques; (2) Development of a damage function analysis (DFA) which would help in predicting the accumulation of damage due to pitting corrosion in an environment prototypical of DOE liquid waste systems; (3) Experimental measurement of crack growth rate, acoustic emission signals and coupling currents for fracture in carbon and low alloy steels as functions of mechanical (stress intensity), chemical (conductivity), electrochemical (corrosion potential, ECP), and microstructural (grain size, precipitate size, etc) variables in a systematic manner, with particular attention being focused on the structure of the noise in the current and its correlation with the acoustic emissions; (4) Development of fracture mechanisms for carbon and low alloy steels that are consistent with the crack growth rate, coupling current data and acoustic emissions; (5) Inserting advanced crack growth rate models for SCC into existing deterministic codes for predicting the evolution of corrosion damage in DOE liquid waste storage tanks; (6) Computer simulation of the anodic and cathodic activity on the surface of the steel samples

  3. Development of Advanced Electrochemical Emission Spectroscopy for Monitoring Corrosion in Simulated DOE Liquid Waste

    Energy Technology Data Exchange (ETDEWEB)

    Digby Macdonald; Brian Marx; Balaji Soundararajan; Morgan Smith

    2005-07-28

    The different tasks that have been carried out under the current program are as follows: (1) Theoretical and experimental assessment of general corrosion of iron/steel in borate buffer solutions by using electrochemical impedance spectroscopy (EIS), ellipsometry and XPS techniques; (2) Development of a damage function analysis (DFA), which would help in predicting the accumulation of damage due to pitting corrosion in an environment prototypical of DOE liquid waste systems; (3) Experimental measurement of crack growth rate, acoustic emission signals, and coupling currents for fracture in carbon and low alloy steels as functions of mechanical (stress intensity), chemical (conductivity), electrochemical (corrosion potential, ECP), and microstructural (grain size, precipitate size, etc) variables in a systematic manner, with particular attention being focused on the structure of the noise in the current and its correlation with the acoustic emissions; (4) Development of fracture mechanisms for carbon and low alloy steels that are consistent with the crack growth rate, coupling current data and acoustic emissions; (5) Inserting advanced crack growth rate models for SCC into existing deterministic codes for predicting the evolution of corrosion damage in DOE liquid waste storage tanks; (6) Computer simulation of the anodic and cathodic activity on the surface of the steel samples in order to exactly predict the corrosion mechanisms; (7) Wavelet analysis of EC noise data from steel samples undergoing corrosion in an environment similar to that of the high level waste storage containers, to extract data pertaining to general, pitting and stress corrosion processes, from the overall data. The work has yielded a number of important findings, including an unequivocal demonstration of the role of chloride ion in passivity breakdown on nickel in terms of cation vacancy generation within the passive film, the first detection and characterization of individual micro fracture

  4. Generation of powerful terahertz emission in a beam-driven strong plasma turbulence

    OpenAIRE

    Arzhannikov, A.V.; Timofeev, I. V.

    2012-01-01

    Generation of terahertz electromagnetic radiation due to coalescence of upper-hybrid waves in the long-wavelength region of strong plasma turbulence driven by a high-current relativistic electron beam in a magnetized plasma is investigated. The width of frequency spectrum as well as angular characteristics of this radiation for various values of plasma density and turbulence energy are calculated using the simple theoretical model adequately describing beam-plasma experiments at mirror traps....

  5. Optical emission spectroscopy of excited atoms sputtered on a Ti surface under irradiation with multicharged Ar ions

    Energy Technology Data Exchange (ETDEWEB)

    Motohashi, K [Department of Applied Physics, Tokyo University of Agriculture and Technology, 2-24-16 Koganei-shi, Tokyo 184-8588 (Japan); Saitoh, Y [Department of Advanced Radiation Technology, Takasaki Advanced Radiation Research Institute, Japan Atomic Energy Agency (JAEA), Takasaki, Gunma 370-1292 (Japan); Kitazawa, S, E-mail: motohasi@cc.tuat.ac.j [Division of ITER Project, Fusion Research Development, Japan Atomic Energy Agency (JAEA), Naka, Ibaraki 311-0193 (Japan)

    2009-04-01

    Optical emission spectroscopy of excited atoms was carried out in order to investigate the sputtering processes on solid surfaces under irradiation of slow, multicharged ions. Many atomic lines of Ti I (neutral) and Ti II (single-charged ions) were observed in wavelengths from 250 to 750 nm with irradiation by Ar{sup 3+} (30 keV) on a Ti surface which was placed in a low pressure O{sub 2} atmosphere. The emission intensity of Ti I (520 nm) decreased monotonically with an increase of O{sub 2} partial pressure, whereas that of Ti I / II (670 nm, a 2nd order wavelength of 335 nm) slightly increased. From a semi-logarithmic plot of emission intensity for the 670 nm spectrum as a function of distance from the surface, the mean velocity of the excited Ti atoms and ions in a normal direction parallel to the surface, or

  6. Emission Line Astronomy - Coronagraphic Tunable Narrow Band Imaging and Integral Field Spectroscopy. Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose to continue our program of emission line astronomy featuring three areas of emphasis: 1) The distribution and nature of high redshift emission line...

  7. Laser Induced Emission Spectroscopy of Cold and Isolated Neutral PAHs and PANH: Implications for the red rectangle emission

    Science.gov (United States)

    Bejaoui, Salma; Salama, Farid; Sciamma O'Brien, Ella

    2016-06-01

    Blue luminescence (BL) in the emission spectra of the red rectangle centered on the bright star HD44179 is recently reported by Vijh et al [1]. This results is consistent with the broad band polarization measurements obtained in 1980 by Schmidt et al. Both experimental and theoretical studies support that BL emission could be attributed the luminescence of Polycyclic Aromatic Hydrocarbon (PAH) excited with ultraviolet light from the center of the star [4 and reference therein]. The abundance on N to C in the interstellar medium suggest also that nitrogen substituted PAH (PANH) are likely abundant in the interstellar medium [3]. They exhibit similar features as PAHs and could contribute to the unidentified spectral bands. Comparing the BL to laboratory spectra obtained on similar environment is crucial for the identification of interstellar molecules. We present in this works the absorption and the laser induced emission spectra of several isolated and cold PAHs and PANHs. Laser induced emission was performed first to PAHs and PANHs isolated in Argon matrix at 10 K. Then, measurements are performed with the supersonic jet technique of the COSmIC laboratory facility at NASA Ames. We focus, here, on the emission spectra (fluorescence and (or) phosphorescence) of these molecules and we discuss their contributions to the blue luminescence emission in the Red Rectangle nebula.[1] Vijh,U.P., Witt. A.N. & Gordon,K.D, APJ, 606, L69 (2004)[2] Schmidt, G. D., Cohen, M. & Margon, B., ApJ, 239L.133S (1980)[3] Spitzer, L., Physical Processes in the Interstellar Medium (New York Wiley-Interscience) (1978)[4] Salama, F., Galazutdinov, G. A., Kre lowski, J., Allamandola, L. J., & Musaev, F. A. ApJ, 526,(1999)

  8. A new beam emission polarimetry diagnostic for measuring the magnetic field line angle at the plasma edge of ASDEX Upgrade

    Science.gov (United States)

    Viezzer, E.; Dux, R.; Dunne, M. G.

    2016-11-01

    A new edge beam emission polarimetry diagnostic dedicated to the measurement of the magnetic field line angle has been installed on the ASDEX Upgrade tokamak. The new diagnostic relies on the motional Stark effect and is based on the simultaneous measurement of the polarization direction of the linearly polarized π (parallel to the electric field) and σ (perpendicular to the electric field) lines of the Balmer line Dα. The technical properties of the system are described. The calibration procedures are discussed and first measurements are presented.

  9. CZT strip detectors for imaging and spectroscopy: Collimated beam and ASIC readout experiments

    Energy Technology Data Exchange (ETDEWEB)

    Kurczynski, P. [Univ. of Maryland, College Park, MD (United States); Krizmanic, J.F.; Parsons, A. [Goddard Space Flight Center, Greenbelt, MD (United States)

    1996-12-31

    We report the status of ongoing investigations into Cadmium Zinc Telluride (CZT) strip detectors for application in hard x-ray astronomy. We have instrumented a nine strip by nine strip region of a two sided strip detector made in our detector fabrication facility. In order to measure the position resolution of our detectors, we have implemented a collimated beam that concentrates radiation to a spot size less than the strip width of our detector. We have also performed charge collection studies as a function of incident photon energy and bias voltage with a single sided, 100{mu}m pitch CZT strip detector wire bonded to an SVX ASIC charge amplifier. The detectors exhibited excellent strip uniformity in terms of photon count rate and spectroscopic information.

  10. Absorption and emission of (In,Ga)N/GaN quantum wells grown by molecular beam epitaxy

    Energy Technology Data Exchange (ETDEWEB)

    Siozade, L.; Disseix, P.; Vasson, A.; Leymarie, J. [CNRS, Aubiere (France). LASMEA; Damilano, B.; Grandjean, N.; Massies, J. [CNRS, Valbonne (France). CRHEA

    2001-01-01

    Thermally detected optical absorption (TDOA) and photoluminescence experiments are carried out on In{sub 0.16}Ga{sub 0.84}N/GaN multi-quantum wells (MQWs) grown by molecular beam epitaxy on (0001) sapphire substrates. A model proposed to adjust the TDOA line shape, allows to deduce the band-edge energies, the absorption coefficients and the broadening parameters of the (In,Ga)N MQWs for different thicknesses. The Fabry-Perot oscillations, which structure the TDOA spectra, are considered in this modelling to accurately account for the experimental data. The emission, which covers the whole visible spectrum at room temperature, is achieved by varying the thickness from 1.5 to 5 nm. A very large Stokes shift between the emission and absorption energies is deduced at low temperature, for the (In,Ga)N MQWs. (orig.)

  11. High resolution photoelectron spectroscopy and femtosecond intramolecular dynamics using supersonic molecular beams

    Energy Technology Data Exchange (ETDEWEB)

    Niu, B.

    1992-09-01

    High resolution He I[alpha] photoelectron spectroscopy of formaldehyde and ketene and their deuterated compounds, are reported. The combination of a (H2CO) double-pass high-resolution electron-energy analyzer and effective rotational cooling of the sample by supersonic expansion enable the spectroscopy of these molecular cations. The vibrational autocorrelation functions are calculated from the high-resolution photoelectron spectra, shedding light on the ultrafast intramolecular dynamics of the molecular cations. This study reveals much more vibrational structural detail in the first electronic excited state of H2CO cations. The first electronic excited state of H2CO cations may have nonplanar equilibrium geometry. Strong isotope effects on vibronic (vibrational) coupling are observed in the second electronic excited state of H2CO. Vibrational autocorrelation functions are calculated for all four observed electronic states of H2CO. The correlation function of the first electronic excited state of H2CO shows a slow decay rate on the femtosecond time scale. The ultrafast decay of the H2CO cations in the third electronic excited state implies that dissociation and intramolecular processes are the main decay pathways. The present spectra of the ground states of ketene cations have more fine structure than before. The AIEs of the first and fifth excited states are determined unambiguously more accurately. The doublet-like fine structures present in the lint excited state of ketene implies the excitation of a soft'' mode not observed before. The vibrational autocorrelation functions are calculated for 4 of the 6 observed electronic states. The dynamics of the ground states of the cations are characterized by a wave packet oscillating with small amplitude around the minimum on the upper PES. The decay dynamics of the first and the fifth excited states of ketene are characterized by ultra-fast intramolecular processes like predissociation.

  12. High resolution photoelectron spectroscopy and femtosecond intramolecular dynamics using supersonic molecular beams

    Energy Technology Data Exchange (ETDEWEB)

    Niu, B.

    1992-09-01

    High resolution He I{alpha} photoelectron spectroscopy of formaldehyde and ketene and their deuterated compounds, are reported. The combination of a (H2CO) double-pass high-resolution electron-energy analyzer and effective rotational cooling of the sample by supersonic expansion enable the spectroscopy of these molecular cations. The vibrational autocorrelation functions are calculated from the high-resolution photoelectron spectra, shedding light on the ultrafast intramolecular dynamics of the molecular cations. This study reveals much more vibrational structural detail in the first electronic excited state of H2CO cations. The first electronic excited state of H2CO cations may have nonplanar equilibrium geometry. Strong isotope effects on vibronic (vibrational) coupling are observed in the second electronic excited state of H2CO. Vibrational autocorrelation functions are calculated for all four observed electronic states of H2CO. The correlation function of the first electronic excited state of H2CO shows a slow decay rate on the femtosecond time scale. The ultrafast decay of the H2CO cations in the third electronic excited state implies that dissociation and intramolecular processes are the main decay pathways. The present spectra of the ground states of ketene cations have more fine structure than before. The AIEs of the first and fifth excited states are determined unambiguously more accurately. The doublet-like fine structures present in the lint excited state of ketene implies the excitation of a ``soft`` mode not observed before. The vibrational autocorrelation functions are calculated for 4 of the 6 observed electronic states. The dynamics of the ground states of the cations are characterized by a wave packet oscillating with small amplitude around the minimum on the upper PES. The decay dynamics of the first and the fifth excited states of ketene are characterized by ultra-fast intramolecular processes like predissociation.

  13. Optical emission spectroscopy characterizations of micro-air plasma used for simulation of cell membrane poration

    Science.gov (United States)

    Zerrouki, A.; Motomura, H.; Ikeda, Y.; Jinno, M.; Yousfi, M.

    2016-07-01

    A micro-air corona discharge, which is one of the plasmas successfully used for gene transfection in terms of high transfection and cell viability rates, is characterized by optical emission spectroscopy. This non-equilibrium low temperature plasma is generated from the tip of a pulsed high voltage micro-tube (0.2 mm inner diameter and 0.7 mm for outer diameter) placed 2 mm in front of a petri dish containing deionized water and set on a grounded copper plate. The electron temperature, equal to about 6.75 eV near the electrode tip and decreased down to 3.4 eV near the plate, has been estimated, with an error bar of about 30%, from an interesting approach based on the experimental ratio of the closest nitrogen emission spectra of \\text{N}2+ (FNS) at 391.4 nm and N2(SPS) at 394.3 nm. This is based on one hand on a balance equation between creations and losses of the excited upper levels of these two UV spectra and on the other hand on the electron impact rates of the creation of these upper levels calculated from solution of the multi-term Boltzmann equation. Then using the measured Hα spectrum, electron density n e has been estimated from Stark broadening versus the inter-electrode position with an average error bar of about 50%. n e  ≈  1  ×  1015 cm-3 is near the tip coherent with the usual magnitude of electron density in the streamer head developed near the tip of the corona discharges. Rotational temperatures, estimated from comparison of synthetic and experimental spectra of OH(A  -  X), \\text{N}2+ (FNS) at 391.4 nm, and N2(SPS) at 337 nm are respectively equal to 2350 K, 2000 K and 700 K in the gap space. This clearly underlines a thermal non-equilibrium of the corresponding excited species generated inside the thin streamer filaments. But, due to the high dilution of these species in the background gas, these high rotational temperatures do not affect the mean gas temperature that remains close to 300

  14. Spectroscopy with trapped highly charged ions

    Energy Technology Data Exchange (ETDEWEB)

    Beiersdorfer, P

    2008-01-23

    We give an overview of atomic spectroscopy performed on electron beam ion traps at various locations throughout the world. Spectroscopy at these facilities contributes to various areas of science and engineering, including but not limited to basic atomic physics, astrophysics, extreme ultraviolet lithography, and the development of density and temperature diagnostics of fusion plasmas. These contributions are accomplished by generating, for example, spectral surveys, making precise radiative lifetime measurements, accounting for radiative power emitted in a given wavelength band, illucidating isotopic effects, and testing collisional-radiative models. While spectroscopy with electron beam ion traps had originally focused on the x-ray emission from highly charged ions interacting with the electron beam, the operating modes of such devices have expanded to study radiation in almost all wavelength bands from the visible to the hard x-ray region; and at several facilities the ions can be studied even in the absence of an electron beam. Photon emission after charge exchange or laser excitation has been observed, and the work is no longer restricted to highly charged ions. Much of the experimental capabilities are unique to electron beam ion traps, and the work performed with these devices cannot be undertaken elsewhere. However, in other areas the work on electron beam ion traps rivals the spectroscopy performed with conventional ion traps or heavy-ion storage rings. The examples we present highlight many of the capabilities of the existing electron beam ion traps and their contributions to physics.

  15. Electric and Magnetic Field Measurements in High Energy Electron Beam Diode Plasmas using Optical Spectroscopy

    Science.gov (United States)

    Johnston, Mark; Patel, Sonal; Kiefer, Mark; Biswas, S.; Doron, R.; Stambulchik, E.; Bernshtam, V.; Maron, Yitzhak

    2016-10-01

    The RITS accelerator (5-11MV, 100-200kA) at Sandia National Laboratories is being used to evaluate the Self-Magnetic Pinch (SMP) diode as a potential flash x-ray radiography source. This diode consists of a small, hollowed metal cathode and a planar, high atomic mass anode, with a small vacuum gap of approximately one centimeter. The electron beam is focused, due to its self-field, to a few millimeters at the target, generating bremsstrahlung x-rays. During this process, plasmas form on the electrode surfaces and propagate into the vacuum gap, with a velocity of a 1-10 cm's/microseconds. These plasmas are measured spectroscopically using a Czerny-Turner spectrometer with a gated, ICCD detector, and input optical fiber array. Local magnetic and electric fields of several Tesla and several MV/cm were measured through Zeeman splitting and Stark shifting of spectral lines. Specific transitions susceptible to quantum magnetic and electric field effects were utilized through the application of dopants. Data was analyzed using detailed, time-dependent, collisional-radiative (CR) and radiation transport modeling. Recent results will be presented. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

  16. Multi-epoch Spectroscopy of Dwarf Galaxies with AGN Signatures: Identifying Sources with Persistent Broad H-alpha Emission

    CERN Document Server

    Baldassare, Vivienne F; Gallo, Elena; Greene, Jenny E; Graur, Or; Geha, Marla; Hainline, Kevin; Carroll, Christopher M; Hickox, Ryan C

    2016-01-01

    We use time-domain optical spectroscopy to distinguish between broad emission lines powered by accreting black holes (BHs) or stellar processes (i.e., supernovae) for 16 galaxies identified as AGN candidates by Reines et al. (2013). 14 of these have star-formation--dominated narrow-line emission ratios, one is a narrow-line AGN, and the last is a star-forming--AGN composite. We find that broad H$\\alpha$ emission has faded for 11/16 targets, based on spectra taken with the Magellan Echellette Spectrograph (MagE), the Dual Imaging Spectrograph, and the Ohio State Multi-Object Spectrograph with baselines ranging from 5 to 14 years. The 11 faded systems all have narrow-line ratios consistent with recent star formation, suggesting the broad emission for those targets was produced by a transient stellar process. The two objects with narrow-line AGN signatures (RGG 9 and RGG 119) have persistent broad H$\\alpha$ emission consistent with previous SDSS observations. The final three star-forming objects are classified a...

  17. Dynamics of double-pulse laser produced titanium plasma inferred from thin film morphology and optical emission spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Krstulović, N., E-mail: niksak@ifs.hr [Institute of Physics, Bijenička 46, HR-10000 Zagreb (Croatia); Salamon, K., E-mail: ksalamon@ifs.hr [Institute of Physics, Bijenička 46, HR-10000 Zagreb (Croatia); Modic, M., E-mail: martina.modic@ijs.si [Jožef Stefan Institute, Jamova 39, 1001 Ljubljana (Slovenia); Bišćan, M., E-mail: mbiscan@ifs.hr [Institute of Physics, Bijenička 46, HR-10000 Zagreb (Croatia); Milat, O., E-mail: milat@ifs.hr [Institute of Physics, Bijenička 46, HR-10000 Zagreb (Croatia); Milošević, S., E-mail: slobodan@ifs.hr [Institute of Physics, Bijenička 46, HR-10000 Zagreb (Croatia)

    2015-05-01

    In this paper, dynamics of double-pulse laser produced titanium plasma was studied both directly using optical emission spectroscopy (OES) and indirectly from morphological properties of deposited thin films. Both approaches yield consistent results. Ablated material was deposited in a form of thin film on the Si substrate. During deposition, plasma dynamics was monitored using optical emission spectroscopy with spatial and temporal resolutions. The influence of ablation mode (single and double) and delay time τ (delay between first and second pulses in double-pulse mode) on plasma dynamics and consequently on morphology of deposited Ti-films was studied using X-ray reflectivity and atomic force microscopy. Delay time τ was varied from 170 ns to 4 μs. The results show strong dependence of both emission signal and Ti-film properties, such as thickness, density and roughness, on τ. In addition, correlation of average density and thickness of film is observed. These results are discussed in terms of dependency of angular distribution and kinetic energy of plasma plume particles on τ. Advantages of using double-pulse laser deposition for possible application in thin film production are shown. - Highlights: • Ti-thin films produced by single and double pulse laser ablation mode. • Ablation mode and delay time influenced plasma plume and film characteristics. • Films are most compact for optimized delay time (thinnest, smoothest and most dense). • Plasma dynamics can be inferred from film characteristics.

  18. Optical Emission Spectroscopy Study of Competing Phases of Electrons in the Second Landau Level.

    Science.gov (United States)

    Levy, A L; Wurstbauer, U; Kuznetsova, Y Y; Pinczuk, A; Pfeiffer, L N; West, K W; Manfra, M J; Gardner, G C; Watson, J D

    2016-01-01

    Quantum phases of electrons in the filling factor range 2≤ν≤3 are probed by the weak optical emission from the partially populated second Landau level and spin wave measurements. Observations of optical emission include a multiplet of sharp peaks that exhibit a strong filling factor dependence. Spin wave measurements by resonant inelastic light scattering probe breaking of spin rotational invariance and are used to link this optical emission with collective phases of electrons. A remarkably rapid interplay between emission peak intensities manifests phase competition in the second Landau level.

  19. Development of Advanced Electrochemical Emission Spectroscopy for Monitoring Corrosion in Simulated DOE Liquid Waste

    Energy Technology Data Exchange (ETDEWEB)

    Digby D. Macdonald; Brian M. Marx; Sejin Ahn; Julio de Ruiz; Balaji Soundararaja; Morgan Smith; and Wendy Coulson

    2008-01-15

    Various forms of general and localized corrosion represent principal threats to the integrity of DOE liquid waste storage tanks. These tanks, which are of a single wall or double wall design, depending upon their age, are fabricated from welded carbon steel and contain a complex waste-form comprised of NaOH and NaNO{sub 3}, along with trace amounts of phosphate, sulfate, carbonate, and chloride. Because waste leakage can have a profound environmental impact, considerable interest exists in predicting the accumulation of corrosion damage, so as to more effectively schedule maintenance and repair. The different tasks that are being carried out under the current program are as follows: (1) Theoretical and experimental assessment of general corrosion of iron/steel in borate buffer solutions by using electrochemical impedance spectroscopy (EIS), ellipsometry and XPS techniques; (2) Development of a damage function analysis (DFA) which would help in predicting the accumulation of damage due to pitting corrosion in an environment prototypical of DOE liquid waste systems; (3) Experimental measurement of crack growth rate, acoustic emission signals and coupling currents for fracture in carbon and low alloy steels as functions of mechanical (stress intensity), chemical (conductivity), electrochemical (corrosion potential, ECP), and microstructural (grain size, precipitate size, etc) variables in a systematic manner, with particular attention being focused on the structure of the noise in the current and its correlation with the acoustic emissions; (4) Development of fracture mechanisms for carbon and low alloy steels that are consistent with the crack growth rate, coupling current data and acoustic emissions; (5) Inserting advanced crack growth rate models for SCC into existing deterministic codes for predicting the evolution of corrosion damage in DOE liquid waste storage tanks; (6) Computer simulation of the anodic and cathodic activity on the surface of the steel samples

  20. OPEN PATH TUNABLE DIODE LASER ABSORPTION SPECTROSCOPY FOR ACQUISITION OF FUGITIVE EMISSION FLUX DATA

    Science.gov (United States)

    Air pollutant emission from unconfined sources is an increasingly important environmental issue. The U.S. EPA has developed a gorund-based optical remote sensing method that enables direct measurement of fugitive emission flux from large area sources. Open-path Fourier transfor...

  1. Photodissociation dynamics of the methyl perthiyl radical at 248 and 193 nm using fast-beam photofragment translational spectroscopy

    Science.gov (United States)

    Harrison, Aaron W.; Ryazanov, Mikhail; Sullivan, Erin N.; Neumark, Daniel M.

    2016-07-01

    The photodissociation dynamics of the methyl perthiyl radical (CH3SS) have been investigated using fast-beam coincidence translational spectroscopy. Methyl perthiyl radicals were produced by photodetachment of the CH3SS- anion followed by photodissociation at 248 nm (5.0 eV) and 193 nm (6.4 eV). Photofragment mass distributions and translational energy distributions were measured at each dissociation wavelength. Experimental results show S atom loss as the dominant (96%) dissociation channel at 248 nm with a near parallel, anisotropic angular distribution and translational energy peaking near the maximal energy available to ground state CH3S and S fragments, indicating that the dissociation occurs along a repulsive excited state. At 193 nm, S atom loss remains the major fragmentation channel, although S2 loss becomes more competitive and constitutes 32% of the fragmentation. The translational energy distributions for both channels are very broad at this wavelength, suggesting the formation of the S2 and S atom products in several excited electronic states.

  2. Effect of Surface Hydrogen Coverage on Field Emission Properties of DiamondFilms Investigated by High-Resolution Electron Energy Loss Spectroscopy

    Institute of Scientific and Technical Information of China (English)

    WANG Yu-Guang; XIONG Yan-Yun; LIN Zhang-Da; FENG Ke-An; GU Chang-Zhi; JIN Zeng-Sun

    2000-01-01

    The influence of surface hydrogen coverage on the electron field emission of diamond films was investigated by high-resolution electron energy loss spectroscopy. It was found that hydrogen plasma treatment increased the surface hydrogen coverage while annealing caused hydrogen desorption and induced surface reconstruction. Field electron emission measurements manifested that increase of surface hydrogen coverage could improve the field emission properties, due to the decrease of electron affinity of the diamond .surface hy hvdrogen adsorption.

  3. Radio imaging spectroscopy of synchrotron emission associated with a CME on the 14th of August 2010

    Science.gov (United States)

    Bain, Hazel; Krucker, S.; Saint-Hilaire, P.; Raftery, C.

    2013-07-01

    We present Nancay Radioheliograph observations of a moving type IV solar radio burst which occurred in association with a CME on the 14th of August 2010. The event was well observed at extreme ultraviolet wavelengths by the Atmospheric Imaging Assembly onboard the Solar Dynamics Observatory, the SWAP instrument onboard Proba2 and by the LASCO white light coronograph. The burst emission was found to be cospatial with the core of the CME. Using radio imaging spectroscopy we are able to characterize the underlying electron distribution and plasma parameters within the source. Fitted spectra reveal a clear power law component consistent with optically thin synchrotron emission from accelerated electrons trapped in the erupting flux rope. As is often observed in type IV bursts, polarization measurements show the source to be moderately polarized during the peak of the burst, before steadily increasing to around 70% as the brightness temperature of the burst decays.

  4. Investigation of the atomic emission spectroscopy of F atoms and CF2 molecules in CF4 plasma processing

    Science.gov (United States)

    Jin, Huiliang; Li, Jie; Tang, Caixue; Deng, Wenhui; Chen, Xianhua

    2016-10-01

    The surface chemistry reaction involved in the processing of Atmospheric Pressure Plasma Jet (APPJ) produced from CF4 precursor has been explored. The atomic emission spectroscopy of F atoms and CF2 molecules was investigated as they contribute to substrate etching and FC film formation during APPJ processing. Optical emission spectroscopy (OES) spectra were acquired for CF4 plasma, relative concentrations of excited state species of F atoms and CF2 molecules were also dependent upon plasma parameters. The densities of F atoms increased dramatically with increasing applied RF power, whereas CF2 molecules decreased monotonically over the same power range, the subsequent electron impacted decomposition of plasma species after CF4 precursor fragmentation. The spectrum of the F atoms and CF2 molecules fallowed the same tendency with the increasing concentration of gas CF4, reaching the maximum at the 20sccm and 15sccm respectively, and then the emission intensity of reactive atoms decreased with more CF4 molecules participating. Addition certain amount O2 into CF4 plasma resulted in promoting CF4 dissociation, O2 can easily react with the dissociation product of CF2 molecules, which inhibit the compound of the F atoms, so with the increasing concentration of O2, the concentration of the CF2 molecules decreased and the emission intensities of F atoms showed the maximum at the O2/CF4 ratio of 20%. These results have led to the development of a scheme that illustrates the mechanisms of surface chemistry reaction and the affection of plasma parameters in CF4 plasma systems with respect to F and CF2 gas-phase species.

  5. X-ray continuum emission spectroscopy from hot dense matter at Gbar pressures

    Energy Technology Data Exchange (ETDEWEB)

    Kraus, D., E-mail: dominik.kraus@berkeley.edu; Falcone, R. W. [Department of Physics, University of California, Berkeley, California 94720 (United States); Döppner, T.; Kritcher, A. L.; Bachmann, B.; Collins, G. W.; Hawreliak, J. A.; Landen, O. L.; Ma, T.; Le Pape, S.; Swift, D. C. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Chapman, D. A. [Plasma Physics Group, Radiation Physics Department, AWE plc, Reading RG7 4PR, United Kingdom and Centre for Fusion, Space and Astrophysics, University of Warwick, Coventry CV4 7AL (United Kingdom); Glenzer, S. H. [SLAC National Accelerator Laboratory, Menlo Park, California 94309 (United States); Neumayer, P. [GSI Helmholtzzentrum für Schwerionenforschung, 64291 Darmstadt (Germany)

    2014-11-15

    We have measured the time-resolved x-ray continuum emission spectrum of ∼30 times compressed polystyrene created at stagnation of spherically convergent shock waves within the Gbar fundamental science campaign at the National Ignition Facility. From an exponential emission slope between 7.7 keV and 8.1 keV photon energy and using an emission model which accounts for reabsorption, we infer an average electron temperature of 375 ± 21 eV, which is in good agreement with HYDRA-1D simulations.

  6. Evidence of satellite valley position in GaN by photoexcited field emission spectroscopy

    Science.gov (United States)

    Yilmazoglu, O.; Pavlidis, D.; Hartnagel, H. L.; Evtukh, A.; Litovchenko, V.; Semenenko, N.

    2008-06-01

    GaN field emitter rods with nanometer diameter were fabricated by photoelectrochemical etching on a n+-GaN substrate. Their electron field emission properties were investigated under ultraviolet (UV) illumination. The Fowler-Nordheim plots of the emission current show different slopes for nonilluminated and UV illuminated devices. A model based on the electron emission from valleys having different specific electron affinities is proposed to explain the experimental results. In the absence of illumination, the GaN rods are almost fully depleted and emission takes place only from the lower valley. Upon UV illumination and presence of a high electric field at the emitter tip, the upper valley of the conduction band appears to be occupied by electrons generated at the valence band. The energy difference between the lower and upper valleys was determined to be 1.15eV and is in good agreement with formerly published theoretical and measured values.

  7. The Development of Cavity Ringdown Spectroscopy as a Toxic Metal Continuous Emission Monitor

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Goeroge P. Miller; Dr. Christopher B. Winstead

    2001-12-04

    Innovative program to explore the viability of using Cavity Ringdown Spectroscopy (CRDS) for trace analysis and monitoring of remediation processes for hazardous and radioactive wastes. Cavity ringdown spectroscopy is a measurement of the rate of absorption of a sample within a closed optical cavity rather than the standard measurement of the avsorved signal strength over a given sample path. It is a technique capable of providing ultra-sensitive absorption measurements in hostile environments using commercially available easy-to-use pulsed lasers. The inherent high sensitivity stems from both the long effective sample pathlengths possible and the relaxed constraints on the accuracy of the measurement of the cavity decay time.

  8. Characterization of RF He-N2/Ar mixture plasma via Langmuir probe and optical emission spectroscopy techniques

    Science.gov (United States)

    Younus, Maria; Rehman, N. U.; Shafiq, M.; Hussain, S. S.; Zakaullah, M.; Zaka-ul-Islam, M.

    2016-08-01

    A Magnetic Pole Enhanced inductively coupled RF H e - N 2 / A r plasma is characterized using a Langmuir probe and optical emission spectroscopy (OES) techniques. The effect of helium mixing on electron density ( n e ) and temperature ( T e ) , electron energy probability functions (EEPFs), [ N ] atomic density, and N 2 dissociation is investigated. A Langmuir probe and a zero slope method based on trace rare gas-optical emission spectroscopy (TRG-OES) are employed to measure the electron temperature. It is noted that the electron temperature shows an increasing trend for both methods. However, the temperature measured by a zero slope method T e ( Z . S ) approaches the temperature measured by a Langmuir probe; T e ( L . P ) at 56% and above helium concentration in the discharge. "Advance actinometry" is employed to monitor the variation in [ N ] atomic density with helium concentration and gas pressure. It is noted that [ N ] atomic density increases at 56% and above helium in the discharge, which is consistent with the trend of electron temperature and EEPFs. A drastic enhancement in N 2 dissociation fraction D 1 determined by "advance actinometry" is noted at 56% and above helium concentration in the mixture due to modifications in different population and depopulation mechanisms. However, it is also noted that the dissociation fraction D 2 determined by intensity ratio method increases linearly with helium addition.

  9. Flash Spectroscopy: Emission Lines from the Ionized Circumstellar Material around $<10$-Day-Old Type II Supernovae

    CERN Document Server

    Khazov, D; Gal-Yam, A; Manulis, I; Rubin, A; Kulkarni, S R; Arcavi, I; Kasliwal, M M; Ofek, E O; Cao, Y; Perley, D; Sollerman, J; Horesh, A; Sullivan, M; Filippenko, A V; Nugent, P E; Howell, D A; Cenko, S B; Silverman, J M; Ebeling, H; Taddia, F; Johansson, J; Laher, R R; Surace, J; Rebbapragada, U D; Wozniak, P R; Matheson, T

    2015-01-01

    Supernovae (SNe) embedded in dense circumstellar material (CSM) may show prominent emission lines in their early-time spectra ($\\leq 10$ days after the explosion), owing to recombination of the CSM ionized by the shock-breakout flash. From such spectra ("flash spectroscopy"), we can measure various physical properties of the CSM, as well as the mass-loss rate of the progenitor during the year prior to its explosion. Searching through the Palomar Transient Factory (PTF and iPTF) SN spectroscopy databases from 2009 through 2014, we found 12 Type II SNe showing flash-ionized (FI) signatures in their first spectra. All are younger than 10 days. These events constitute 14\\% of all 84 SNe in our sample having a spectrum within 10 days from explosion, and 18\\% of SNe~II observed at ages $<5$ days, thereby setting lower limits on the fraction of FI events. We classified as "blue/featureless" (BF) those events having a first spectrum which is similar to that of a black body, without any emission or absorption signa...

  10. The performance of the γ-ray tracking array GRETINA for γ-ray spectroscopy with fast beams of rare isotopes

    Science.gov (United States)

    Weisshaar, D.; Bazin, D.; Bender, P. C.; Campbell, C. M.; Recchia, F.; Bader, V.; Baugher, T.; Belarge, J.; Carpenter, M. P.; Crawford, H. L.; Cromaz, M.; Elman, B.; Fallon, P.; Forney, A.; Gade, A.; Harker, J.; Kobayashi, N.; Langer, C.; Lauritsen, T.; Lee, I. Y.; Lemasson, A.; Longfellow, B.; Lunderberg, E.; Macchiavelli, A. O.; Miki, K.; Momiyama, S.; Noji, S.; Radford, D. C.; Scott, M.; Sethi, J.; Stroberg, S. R.; Sullivan, C.; Titus, R.; Wiens, A.; Williams, S.; Wimmer, K.; Zhu, S.

    2017-03-01

    The γ-ray tracking array GRETINA was coupled to the S800 magnetic spectrometer for spectroscopy with fast beams of rare isotopes at the National Superconducting Cyclotron Laboratory on the campus of Michigan State University. We describe the technical details of this powerful setup and report on GRETINA's performance achieved with source and in-beam measurements. The γ-ray multiplicity encountered in experiments with fast beams is usually low, allowing for a simplified and efficient treatment of the data in the γ-ray analysis in terms of Doppler reconstruction and spectral quality. The results reported in this work were obtained from GRETINA consisting of 8 detector modules hosting four high-purity germanium crystals each. Currently, GRETINA consists of 10 detector modules.

  11. Time-resolved characterization of a filamentary argon discharge at atmospheric pressure in a capillary using emission and absorption spectroscopy

    Science.gov (United States)

    Schröter, Sandra; Pothiraja, Ramasamy; Awakowicz, Peter; Bibinov, Nikita; Böke, Marc; Niermann, Benedikt; Winter, Jörg

    2013-11-01

    An argon/nitrogen (0.999/0.001) filamentary pulsed discharge operated at atmospheric pressure in a quartz tube is characterized using voltage-current measurements, microphotography, optical emission spectroscopy (OES) and absorption spectroscopy. Nitrogen is applied as a sensor gas for the purpose of OES diagnostic. The density of argon metastable atoms Ar(3P2) is determined using tunable diode laser absorption spectroscopy (TDLAS). Using a plasma chemical model the measured OES data are applied for the characterization of the plasma conditions. Between intense positive pulses the discharge current oscillates with a damped amplitude. It is established that an electric current flows in this discharge not only through a thin plasma filament that is observed in the discharge image but also through the whole cross section of the quartz tube. A diffuse plasma fills the quartz tube during a time between intense current pulses. Ionization waves are propagating in this plasma between the spike and the grounded area of the tube producing thin plasma channels. The diameter of these channels increases during the pause between the propagation of ionization waves probably because of thermal expansion and diffusion. Inside the channels electron densities of ˜2 × 1013 cm-3, argon metastable densities ˜1014 cm-3 and a reduced electric field about 10 Td are determined.

  12. Poster — Thur Eve — 18: Cherenkov Emission By High-Energy Radiation Therapy Beams: A Characterization Study

    Energy Technology Data Exchange (ETDEWEB)

    Zlateva, Y.; El Naqa, I. [Medical Physics Unit, Department of Oncology, McGill University, Montreal, QC (Canada); Quitoriano, N. [Department of Mining and Materials Engineering McGill University, Montreal, QC (Canada)

    2014-08-15

    We investigate Cherenkov emission (CE) by radiotherapy beams via radiation dose-versus-CE correlation analyses, CE detection optimization by means of a spectral shift towards the near-infrared (NIR) window of biological tissue, and comparison of CE to on-board MV imaging. Dose-CE correlation was investigated via simulation and experiment. A Monte Carlo (MC) CE simulator was designed using Geant4. Experimental phantoms include: water; tissue-simulating phantom composed of water, Intralipid®, and beef blood; plastic phantom with solid water insert. The detector system comprises an optical fiber and diffraction-grating spectrometer incorporating a front/back-illuminated CCD. The NIR shift was carried out with CdSe/ZnS quantum dots (QDs), emitting at (650±10) nm. CE and MV images were acquired with a CMOS camera and electronic portal imaging device. MC and experimental studies indicate a strong linear dose-CE correlation (Pearson coefficient > 0.99). CE by an 18-MeV beam was effectively NIR-shifted in water and a tissue-simulating phantom, exhibiting a significant increase at 650 nm for QD depths up to 10 mm. CE images exhibited relative contrast superior to MV images by a factor of 30. Our work supports the potential for application of CE in radiotherapy online imaging for patient setup and treatment verification, since CE is intrinsic to the beam and non-ionizing and QDs can be used to improve CE detectability, potentially yielding image quality superior to MV imaging for the case of low-density-variability, low-optical-attenuation materials (ex: breast/oropharynx). Ongoing work involves microenvironment functionalization of QDs and application of multi-channel spectrometry for simultaneous acquisition of dosimetric and tumor oxygenation signals.

  13. A Method for Eliminating Beam Steering Error for the Modulated Absorption-Emission Thermometry Technique

    Science.gov (United States)

    2015-01-01

    currently valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. 1. REPORT DATE (DD-MM-YYYY) December 2014 2. REPORT TYPE...Briefing Charts 3. DATES COVERED (From - To) December 2014- January 2015 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER N/A A Method for Eliminating...Jan 2015. PA#14562. 14. ABSTRACT Modulated absorption-emission thermometry (MAET) is a non-intrusive, radiometric technique for measuring line-of

  14. UVES and X-Shooter spectroscopy of the emission line AM CVn systems GP Com and V396 Hya

    Science.gov (United States)

    Kupfer, T.; Steeghs, D.; Groot, P. J.; Marsh, T. R.; Nelemans, G.; Roelofs, G. H. A.

    2016-04-01

    We present time-resolved spectroscopy of the AM CVn-type binaries GP Com and V396 Hya obtained with VLT/X-Shooter and VLT/UV-Visual Echelle Spectrograph (UVES). We fully resolve the narrow central components of the dominant helium lines and determine radial velocity semi-amplitudes of Kspike = 11.7 ± 0.3 km s-1 for GP Com and Kspike = 5.8 ± 0.3 km s-1 for V396 Hya. The mean velocities of the narrow central components show variations from line to line. Compared to calculated line profiles that include Stark broadening we are able to explain the displacements, and the appearance of forbidden helium lines, by additional Stark broadening of emission in a helium plasma with an electron density ne ≃ 5 × 1015 cm-3. More than 30 nitrogen and more than 10 neon lines emission lines were detected in both systems. Additionally, 20 nitrogen absorption lines are only seen in GP Com. The radial velocity variations of these lines show the same phase and velocity amplitude as the central helium emission components. The small semi-amplitude of the central helium emission component, the consistency of phase and amplitude with the absorption components in GP Com as well as the measured Stark effect shows that the central helium emission component, the so-called central-spike, is consistent with an origin on the accreting white dwarf. We use the dynamics of the bright spot and the central-spike to constrain the binary parameters for both systems and find a donor mass of 9.6-42.8 MJupiter for GP Com and 6.1-30.5 MJupiter for V396 Hya. We find an upper limit for the rotational velocity of the accretor of vrot < 46 km s-1 for GP Com and vrot < 59 km s-1 for V396 Hya which excludes a fast rotating accretor in both systems.

  15. Correlation of electron beams and hard x-ray emissions in ISTTOK Tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Jakubowski, L.; Malinowski, K.; Sadowski, M.J.; Zebrowski, J.; Rabinski, M.; Jakubowski, M.J. [National Centre for Nuclear Research (NCBJ), Otwock (Poland); Plyusnin, V.V.; Fernandes, H.; Silva, C.; Duarte, P. [Association Euratom/IST, Instituto de Plasmas e Fusao Nuclear, Instituto Superior Tecnico, Lisboa (Portugal)

    2013-11-15

    The paper reports on experimental studies of electron beams in the ISTTOK tokamak, those were performed by means of an improved four-channel detector. The Cherenkov-type detector measuring head was equipped with four radiators made of two types of alumina-nitrate (AlN) poly-crystals: machinable and translucent ones, both of 10 mm in diameter and 2.5 mm in thickness. The movable support that enabled the whole detectors to be placed inside the tokamak vacuum chamber, at chosen positions along the ISTTOK minor radius. Since the electron energy distribution is one of the most important characteristics of tokamak plasmas, the main aim of the study was to perform estimations of an energy spectrum of the recorded electrons. For this purpose the radiators were coated with molybdenum (Mo) layers of different thickness. The technique based on the use of Cherenkov-type detectors enabled the detection of fast electrons (of energy above 66 keV) and determination of their spatial and temporal characteristics in the ISTTOK experiment. Measurements of hard X-rays (HXR), which were emitted during ISTTOK discharges, have also been performed. Particular attention was paid to the correlation measurements of HXR pulses with run-away electron beams. (copyright 2013 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  16. Development of a new laboratory technique for high-temperature thermal emission spectroscopy of silicate melts

    Science.gov (United States)

    Lee, Rachel J.; Ramsey, Michael S.; King, Penelope L.

    2013-05-01

    the prevalence of glass and molten silicates in volcanic environments, and the important role of surface emissivity in thermal infrared (TIR) measurements, it is imperative to characterize accurately the spectral features associated with silicate glasses and melts. A microfurnace has been developed specifically for use with a laboratory Fourier transform infrared (FTIR) spectrometer to collect the first in situ TIR emission spectra of actively melting and cooling silicate glasses. The construction, implementation, and calibration of the microfurnace spectrometer system are presented here. Initial testing of the microfurnace is also discussed, which includes acquisition of thermal emission spectra of a quartz powder (unmelted), a melted and cooled oligoclase feldspar, and glassy melt of rhyolitic composition. Unlike a solid material, which may only have bending and stretching vibrations within its molecular structure, a fully molten material will exhibit several more degrees of freedom in structural movement, thus changing its spectral character. Differences in spectral behavior and morphology are observed between a glass in a solid state and its molten counterpart, confirming previous field measurements of lower emissivity upon melting. This laboratory microfurnace system has been designed to quantify the TIR emission spectral behavior of glassy materials in various physical states. Ultimately, it is hoped that the microfurnace data will help improve the ability of field-based, airborne, and spaceborne TIR data to characterize glassy volcanic terranes.

  17. Optical emission spectroscopy of point-plane corona and back-corona discharges in air

    Science.gov (United States)

    Czech, T.; Sobczyk, A. T.; Jaworek, A.

    2011-12-01

    Results of spectroscopic investigations and current-voltage characteristics of corona discharge and back discharge on fly-ash layer, generated in point-plane electrode geometry in air at atmospheric pressure are presented in the paper. The characteristics of both discharges are similar but differ in the current and voltage ranges of all the discharge forms distinguished during the experiments. Three forms of back discharge, for positive and negative polarity, were investigated: glow, streamer and low-current back-arc. In order to characterize ionisation and excitation processes in back discharge, the emission spectra were measured and compared with those obtained for normal corona discharge generated in the same electrode configuration but with fly ash layer removed. The emission spectra were measured in two discharge zones: near the tip of needle electrode and near the plate. Visual forms of the discharge were recorded with digital camera and referred to current-voltage characteristics and emission spectra. The measurements have shown that spectral lines emitted by back discharge depend on the form of discharge and the discharge current. From the comparison of the spectral lines of back and normal discharges an effect of fly ash layer on the discharge morphology can be determined. The recorded emission spectra formed by ionised gas and plasma near the needle electrode and fly ash layer are different. It should be noted that in back arc emission, spectral lines of fly ash layer components can be distinguished. On the other hand, in needle zone, the emission of high intensity N2 second positive system and NO γ lines can be noticed. Regardless of these gaseous lines, also atomic lines of dust layer were present in the spectrum. The differences in spectra of back discharge for positive and negative polarities of the needle electrode have been explained by considering the kind of ions generated in the crater in fly ash layer. The aim of these studies is to better

  18. UVES and X-Shooter spectroscopy of the emission line AM CVn systems GP Com and V396 Hya

    CERN Document Server

    Kupfer, T; Groot, P J; Marsh, T R; Nelemans, G; Roelofs, G H A

    2016-01-01

    We present time-resolved spectroscopy of the AM CVn-type binaries GP Com and V396 Hya obtained with VLT/X-Shooter and VLT/UVES. We fully resolve the narrow central components of the dominant helium lines and determine radial velocity semi-amplitudes of $K_{\\rm spike} = 11.7\\pm0.3$ km s$^{-1}$ for GP Com and $K_{\\rm spike} = 5.8\\pm0.3$ km s$^{-1}$ for V396 Hya. The mean velocities of the narrow central components show variations from line to line. Compared to calculated line profiles that include Stark broadening we are able to explain the displacements, and the appearance of forbidden helium lines, by additional Stark broadening of emission in a helium plasma with an electron density $n_e\\simeq 5\\times 10^{15}$ cm$^{-3}$. More than $30$ nitrogen and more than $10$ neon lines emission lines were detected in both systems. Additionally, $20$ nitrogen absorption lines are only seen in GP Com. The radial velocity variations of these lines show the same phase and velocity amplitude as the central helium emission co...

  19. The primary photophysics of the Avena sativa phototropin 1 LOV2 domain observed with time-resolved emission spectroscopy.

    Science.gov (United States)

    van Stokkum, Ivo H M; Gauden, Magdalena; Crosson, Sean; van Grondelle, Rienk; Moffat, Keith; Kennis, John T M

    2011-01-01

    The phototropins are blue-light receptors that base their light-dependent action on the reversible formation of a covalent bond between a flavin mononucleotide (FMN) cofactor and a conserved cysteine in light, oxygen or voltage (LOV) domains. The primary reactions of the Avena sativa phototropin 1 LOV2 domain were investigated by means of time-resolved and low-temperature fluorescence spectroscopy. Synchroscan streak camera experiments revealed a fluorescence lifetime of 2.2 ns in LOV2. A weak long-lived component with emission intensity from 600 to 650 nm was assigned to phosphorescence from the reactive FMN triplet state. This observation allowed determination of the LOV2 triplet state energy level at physiological temperature at 16600 cm(-1). FMN dissolved in aqueous solution showed pH-dependent fluorescence lifetimes of 2.7 ns at pH 2 and 3.9-4.1 ns at pH 3-8. Here, too, a weak phosphorescence band was observed. The fluorescence quantum yield of LOV2 increased from 0.13 to 0.41 upon cooling the sample from 293 to 77 K. A pronounced phosphorescence emission around 600 nm was observed in the LOV2 domain between 77 and 120 K in the steady-state emission.

  20. Cobalt(II) complexation with small biomolecules as studied by 57Co emission Mössbauer spectroscopy

    Science.gov (United States)

    Kamnev, Alexander A.; Perfiliev, Yurii D.; Kulikov, Leonid A.; Tugarova, Anna V.; Kovács, Krisztina; Homonnay, Zoltán; Kuzmann, Ernő

    2017-02-01

    In the emission (57Co) variant of Mössbauer spectroscopy (EMS), the 57Co radionuclide (with a half-life of 9 months) is used that undergoes a nuclear decay 57Co → 57Fe via electron capture followed by the emission of a γ-quantum, the energy of which is modified by the chemical state and the close coordination environment of the parent 57Co atom. While EMS has been used largely in materials science and nuclear chemistry, its high sensitivity can also be of great advantage in revealing fine structural features and for speciation analysis of biological complexes, whenever the 57Co2 + cation can be used directly as the coordinating metal or as a substitute for native cobalt or other metal ions. As such EMS applications are yet rare, in order to reliably interpret emission spectra of sophisticated 57Co2 +-doped biosystems, model EMS studies of simple cobalt biocomplexes are necessary. In this work, EMS spectroscopic data are analysed and discussed for 57Co2 + complexes with a range of small biomolecules of different structures, including 4-n-hexylresorcinol, homoserine lactone and a few amino acids (spectra measured in rapidly frozen dilute aqueous solutions or in the dried state at T = 80 K). The EMS data obtained are discussed with regard to the available literature data related to the coordination modes of the biocomplexes under study.

  1. Factors influencing the accuracy of beam range estimation in proton therapy using prompt gamma emission

    Science.gov (United States)

    Janssen, FMFC; Landry, G.; Cambraia Lopes, P.; Dedes, G.; Smeets, J.; Schaart, D. R.; Parodi, K.; Verhaegen, F.

    2014-08-01

    In-vivo imaging is a strategy to monitor the range of protons inside the patient during radiation treatment. A possible method of in-vivo imaging is detection of secondary ‘prompt’ gamma (PG) photons outside the body, which are produced by inelastic proton-nuclear interactions inside the patient. In this paper, important parameters influencing the relationship between the PG profile and percentage depth dose (PDD) in a uniform cylindrical phantom are explored. Monte Carlo simulations are performed with the new Geant4 based code TOPAS for mono-energetic proton pencil beams (range: 100-250 MeV) and an idealized PG detector. PG depth profiles are evaluated using the inflection point on a sigmoid fit in the fall-off region of the profile. A strong correlation between the inflection point and the proton range determined from the PDD is found for all conditions. Variations between 1.5 mm and 2.7 mm in the distance between the proton range and the inflection point are found when either the mass density, phantom diameter, or detector acceptance angle is changed. A change in cut-off energy of the detector could induce a range difference of maximum 4 mm. Applying time-of-flight discrimination during detection, changing the primary energy of the beam or changing the elemental composition of the tissue affects the accuracy of the range prediction by less than 1 mm. The results indicate that the PG signal is rather robust to many parameter variations, but millimetre accurate range monitoring requires all medium and detector properties to be carefully taken into account.

  2. Time reverse modeling of acoustic emissions in a reinforced concrete beam.

    Science.gov (United States)

    Kocur, Georg Karl; Saenger, Erik H; Grosse, Christian U; Vogel, Thomas

    2016-02-01

    The time reverse modeling (TRM) is applied for signal-based acoustic emission (AE) analysis of reinforced concrete (RC) specimens. TRM uses signals obtained from physical experiments as input. The signals are re-emitted numerically into a structure in a time-reversed manner, where the wavefronts interfere and appear as dominant concentrations of energy at the origin of the AE. The experimental and numerical results presented for selected AE signals confirm that TRM is capable of localizing AE activity in RC caused by concrete cracking. The accuracy of the TRM results is corroborated by three-dimensional crack distributions obtained from X-ray computed tomography images.

  3. Emission Mössbauer spectroscopy of advanced materials for opto- and nano-electronics

    CERN Multimedia

    Olafsson, S; Weyer, G O P; Masenda, H; Dlamini, W B

    Mössbauer Spectroscopy (MS) is a versatile solid state method giving information about probe atom interactions with its nearest neighbours. Simultaneously, information on the probe valence state, site symmetry, and electric and magnetic hyperfine interactions is obtained. MS can be applied in many different contexts in material science and solid state physics. MS using radioactive isotopes, applied for decades at the ISOLDE facilities, has the particular merit of very high sensitivity. This opens up many new possibilities compared to traditional (absorption) Mössbauer spectroscopy. Among them is the possibility of working with very low concentrations (10$^{-4}$ at. ~\\%), where the probe atoms are true dilute impurities. Here we propose four main themes in our Mössbauer investigations for the coming years: \\\\(1) Para-magnetic relaxations in compound semiconductors. \\\\(2) Vacancy diffusion in group IV semiconductors. \\\\(3) Doping of Si-nano-particles. \\\\(4) Investigation of phase change mechanisms in chalcog...

  4. Excitation-emission fluorescence spectroscopy and time-gated Raman microscopy analysis of dental tissues

    Science.gov (United States)

    Mukhin, M.; Sen, S.; Kouklin, Nikolai A.; Skliarov, A.; Dhuru, D. B.; Iacopino, A. M.; Yakovlev, Vladislav V.

    2007-02-01

    We applied two new spectroscopic techniques (time-gated Raman microscopy and excitation-emission fluorescence microspectroscopy) to characterize healthy and carious dental tissues. These methods were used together with visual inspection, DIAGNOdent, optical polarization microscopy, scanning electron microscopy, and chemical microanalysis to get a more detailed picture of chemical and structural transformations in dental tissues as a result of caries development.

  5. Neutron emission spectroscopy of DT plasmas at enhanced energy resolution with diamond detectors

    Science.gov (United States)

    Giacomelli, L.; Nocente, M.; Rebai, M.; Rigamonti, D.; Milocco, A.; Tardocchi, M.; Chen, Z. J.; Du, T. F.; Fan, T. S.; Hu, Z. M.; Peng, X. Y.; Hjalmarsson, A.; Gorini, G.

    2016-11-01

    This work presents measurements done at the Peking University Van de Graaff neutron source of the response of single crystal synthetic diamond (SD) detectors to quasi-monoenergetic neutrons of 14-20 MeV. The results show an energy resolution of 1% for incoming 20 MeV neutrons, which, together with 1% detection efficiency, opens up to new prospects for fast ion physics studies in high performance nuclear fusion devices such as SD neutron spectrometry of deuterium-tritium plasmas heated by neutral beam injection.

  6. The X-ray emission of solar flares generated by anisotropic electron beams

    Science.gov (United States)

    Bogovalov, S. V.; Kelner, S. R.; Kotov, Y. D.

    1987-12-01

    For three types of the initial angle distribution of fast electrons, energy spectra, directivity, and polarization of the bremsstrahlung have been computed with an account for multiple scattering and energy losses. The influence of Compton scattering and of photoabsorption on the observed hard X-ray emission of solar flares has been investigated. It is obtained that the photon spectrum index depends not only on the spectrum of electrons but also on the registered energy range and on the angle of view of the flare. In the 10 - 40 keV range the spectrum is softer at the limb than in the solar disc centre; in the 60 - 360 keV the situation is reverse, the spectrum being softer in the solar disc centre.

  7. [Study of a wire-to-plate positive pulsed corona discharge reactor by emission spectroscopy].

    Science.gov (United States)

    Wang, Shen-Bing; Luo, Zhong-Yang; Zhao, Lei; Xuan, Jian-Yong; Jiang, Jian-Ping; Cen, Ke-Fa

    2011-11-01

    In order to get extensive knowledge of wire-to-plate pulsed corona discharge reactor, the influences of different diameters of wire electrode, different wire-to-plate and wire-to-wire spacing on OH radical generation were experimentally investigated under atmospheric pressure based on emission spectrum, and the spatial distribution of OH radicals in the electric field was also discussed in detail The results showed that OH radicals decrease along the X-axis, and the activation radius is approximately 20 mm; showing a trend of first increase and then decrease along the Y-axis, with the activation radius being more than 30 mm. OH radical has small change as the diameter of wire electrode changes below 2 mm, with a sharp decline as the diameter continues to increase. OH radical emission intensity increases as wire-to-wire spacing increases and decrease as wire-to-plate spacing increases.

  8. Tissue differentiation by means of high resolution optical emission spectroscopy during electrosurgical intervention

    Science.gov (United States)

    Bürger, Ines; Scharpf, Marcus; Hennenlotter, Jörg; Nüßle, Daniela; Spether, Dominik; Neugebauer, Alexander; Bibinov, Nikita; Stenzl, Arnulf; Fend, Falko; Enderle, Markus; Awakowicz, Peter

    2017-01-01

    Electrosurgery is the use of radio-frequency electric current for the cutting of biological tissue e.g. for resection of tumour tissue. In this work, the optical emission of plasma being generated during the electrosurgical procedure is investigated with a high resolution echelle spectrometer to find differences between tumour tissue and normal renal tissue in a pre-clinical ex vivo study. Trace elements like zinc, iron, copper and cadmium are present in the tissue spectra as well as the electrolytes magnesium, calcium, sodium and potassium and some diatomic molecules such as hydroxyl radical, cyano radical, dicarbon, nitrogen monohydride and molecular nitrogen which are mainly dissociated from polyatomic molecules. With the atomic emission line of cadmium at 228.8 nm the treated tissue can be differentiated in tumorous and healthy tissue with correct assignment of 95% for tumour tissue and 92% for normal renal tissue.

  9. The SMARTS Multi-epoch Optical Spectroscopy Atlas (SAMOSA): Using Emission Line Variability to Probe the Location of the Blazar Gamma-emitting Region

    CERN Document Server

    Isler, Jedidah C; Bailyn, C; Smith, P S; Coppi, P; Brady, M; Macpherson, E; Hasan, I; Buxton, M

    2015-01-01

    We present multi-epoch optical spectroscopy of seven southern Fermi-monitored blazars from 2008 - 2013 using the Small and Medium Aperture Research Telescope System (SMARTS), with supplemental spectroscopy and polarization data from the Steward Observatory. We find that the emission lines are much less variable than the continuum; 4 of 7 blazars had no detectable emission line variability over the 5 years. This is consistent with photoionization primarily by an accretion disk, allowing us to use the lines as a probe of disk activity. Comparing optical emission line flux with Fermi $\\gamma$-ray flux and optical polarized flux, we investigate whether relativistic jet variability is related to the accretion flow. In general, we see no such dependence, suggesting the jet variability is likely caused by internal processes like turbulence or shock acceleration rather than a variable accretion rate. However, three sources showed statistically significant emission line flares in close temporal proximity to very large...

  10. Emission and propagation of Saturn kilometric radiation: magneto-ionic modes, beaming pattern and polarization state

    CERN Document Server

    Lamy, L; Zarka, P; Canu, P; Schippers, P; Kurth, W S; Mutel, R L; Gurnett, D A; Menietti, J D; Louarn, P

    2011-01-01

    The Cassini mission crossed the source region of the Saturn kilometric radiation (SKR) on 17 October 2008. On this occasion, the Radio and Plasma Wave Science (RPWS) experiment detected both local and distant radio sources, while plasma parameters were measured in situ by the magnetometer (MAG) and the Cassini Plasma Spectrometer (CAPS). A goniopolarimetric inversion was applied to RPWS 3-antenna electric measurements to determine the wave vector k and the complete state of polarization of detected waves. We identify broadband extraordinary (X) as well as narrowband ordinary (O) mode SKR at low frequencies. Within the source region, SKR is emitted just above the X mode cutoff frequency in a hot plasma, with a typical electron-to-wave energy conversion efficiency of 1% (2% peak). The knowledge of the k-vector is then used to derive the locus of SKR sources in the kronian magnetosphere, that shows X and O components emanating from the same regions. We also compute the associated beaming angle at the source thet...

  11. Development of a Reference Database for Particle-Induced Gamma-ray Emission spectroscopy

    OpenAIRE

    Dimitriou, P.; Becker, H.-W.; Bogdanović-Radović, I.; M. Chiari; Goncharov, A.; Jesus, A. P.; Kakuee, O.; Kiss, A. Z.; Lagoyannis, A.; Räisänen, J.; Strivay, David; Zucchiatti, A.

    2016-01-01

    Particle-Induced Gamma-ray Emission (PIGE) is a powerful analytical technique that exploits the interactions of rapid charged particles with nuclei located near a sample surface to determine the composition and structure of the surface regions of solids by measurement of characteristic prompt γ rays. The potential for depth profiling of this technique has long been recognized, however, the implementation has been limited owing to insufficient knowledge of the physical data and lack of suitabl...

  12. X-ray Absorption and Emission Spectroscopy of the Intergalactic Medium at Small Redshift

    Science.gov (United States)

    Paerels, F.; Rasmussen, A.; Kahn, S.; Herder, J. W.; Vries, C.

    Recent observations with Chandra and XMM-Newton have begun to probe the properties of the intergalactic medium (IGM) at small redshifts. We briefly present a recent new result on resonance absorption by highly ionized oxygen at z ≈ 0 with the Reflection Grating Spectrometer on XMM-Newton, and then discuss the prospects for detecting line emission from the Warm-Hot phase of the IGM.

  13. Comparative measurements of mineral elements in milk powders with laser-induced breakdown spectroscopy and inductively coupled plasma atomic emission spectroscopy.

    Science.gov (United States)

    Lei, W Q; El Haddad, J; Motto-Ros, V; Gilon-Delepine, N; Stankova, A; Ma, Q L; Bai, X S; Zheng, L J; Zeng, H P; Yu, J

    2011-07-01

    Mineral elements contained in commercially available milk powders, including seven infant formulae and one adult milk, were analyzed with inductively coupled plasma atomic emission spectrometry (ICP-AES) and laser-induced breakdown spectroscopy (LIBS). The purpose of this work was, through a direct comparison of the analytical results, to provide an assessment of the performance of LIBS, and especially of the procedure of calibration-free LIBS (CF-LIBS), to deal with organic compounds such as milk powders. In our experiments, the matrix effect was clearly observed affecting the analytical results each time laser ablation was employed for sampling. Such effect was in addition directly observed by determining the physical parameters of the plasmas induced on the different samples. The CF-LIBS procedure was implemented to deduce the concentrations of Mg and K with Ca as the internal reference element. Quantitative analytical results with CF-LIBS were validated with ICP-AES measurements and nominal concentrations specified for commercial milks. The obtained good results with the CF-LIBS procedure demonstrate its capacity to take into account the difference in physical parameters of the plasma in the calculation of the concentrations of mineral elements, which allows a significant reduction of the matrix effect related to laser ablation. We finally discuss the way to optimize the implementation of the CF-LIBS procedure for the analysis of mineral elements in organic materials.

  14. IFU spectroscopy of 10 early-type galactic nuclei - III. Properties of the circumnuclear gas emission

    CERN Document Server

    Ricci, T V; Menezes, R B

    2015-01-01

    Many Early-type galaxies (ETG) have ionized gas emission in their centres that extends to scales of ~ 1kpc. The majority of such objects are classified as LINERs, but the nature of their ionizing source is still not clear. The kinematics associated with these gaseous structures usually shows deviations from a pure rotational motion due to non-gravitational effects or to non-axisymmetric potentials. This is the third of a series of papers that describes a sample of 10 nearby and massive ETG observed with the Gemini Multi-Object Spectrograph in Integral Field mode installed on the Gemini-South telescope. In paper II, we performed spectral synthesis to subtract the stellar components from the data cubes of the sample galaxies in order to study their nuclear spectra. Here, we analyse the circumnuclear gas emission (scales of ~ 100 pc) of the sample galaxies. Circumnuclear gas emission was detected in seven galaxies, all of them classified as LINERs. Pure gaseous discs are found in three galaxies. In two objects, ...

  15. IFU spectroscopy of 10 early type galactic nuclei: II - Nuclear emission line properties

    CERN Document Server

    Ricci, T V; Menezes, R B

    2014-01-01

    Although it is well known that massive galaxies have central black holes, most of them accreting at low Eddington ratios, many important questions still remain open. Among them, are the nature of the ionizing source, the characteristics and frequencies of the broad line region and of the dusty torus. We report observations of 10 early-type galactic nuclei, observed with the IFU/GMOS spectrograph on the Gemini South telescope, analysed with standard techniques for spectral treatment and compared with results obtained with principal component analysis Tomography (Paper I). We performed spectral synthesis of each spaxel of the data cubes and subtracted the stellar component from the original cube, leaving a data cube with emission lines only. The emission lines were decomposed in multi-Gaussian components. We show here that, for eight galaxies previously known to have emission lines, the narrow line region can be decomposed in two components with distinct line widths. In addition to this, broad H$\\alpha$ emissio...

  16. Measuring Organic Molecular Emission in Disks with Low Resolution Spitzer Spectroscopy

    CERN Document Server

    Teske, Johanna K; Carr, John S; Pascucci, Ilaria; Apai, Daniel; Henning, Thomas

    2011-01-01

    We explore the extent to which Spitzer IRS spectra taken at low spectral resolution can be used in quantitative studies of organic molecular emission from disks surrounding low mass young stars. We use Spitzer IRS spectra taken in both the high and low resolution modules for the same sources to investigate whether it is possible to define line indices that can measure trends in the strength of the molecular features in low resolution data. We find that trends in HCN emission strength seen in the high resolution data can be recovered in low resolution data. In examining the factors that influence the HCN emission strength, we find that the low resolution HCN flux is modestly correlated with stellar accretion rate and X-ray luminosity. Correlations of this kind are perhaps expected based on recent observational and theoretical studies of inner disk atmospheres. Our results demonstrate the potential of using the large number of low resolution disk spectra that reside in the Spitzer archive to study the factors t...

  17. No Evidence for Lyman-alpha Emission in Spectroscopy of z > 7 Candidate Galaxies

    CERN Document Server

    Caruana, Joseph; Wilkins, Stephen M; Stanway, Elizabeth R; Lacy, Mark; Jarvis, Matt J; Lorenzoni, Silvio; Hickey, Samantha

    2012-01-01

    We present Gemini/GNIRS spectroscopic observations of 4 z-band (z~7) dropout galaxies and VLT/XSHOOTER observations of one z-band dropout and 3 Y-band (z~8-9) dropout galaxies in the Hubble Ultra Deep Field, which were selected with Wide Field Camera 3 imaging on the Hubble Space Telescope. We find no evidence of Lyman-alpha emission with a typical 5-sigma sensitivity of 5X10^-18erg/cm^2/s, and we use the upper limits on Lyman-alpha flux and the broad-band magnitudes to constrain the rest-frame equivalent widths for this line emission. Accounting for incomplete spectral coverage, we survey 3.0 z-band dropouts and 2.9 Y-band dropouts to a Lyman-alpha rest-frame equivalent width limit > 120Ang (for an unresolved emission line); for an equivalent width limit of 50Ang the effective numbers of drop-outs surveyed fall to 1.2 z-band drop-outs and 1.5 Y-band drop-outs. A simple model where the fraction of high rest-frame equivalent width emitters follows the trend seen at z=3-6.5 is inconsistent with our non-detectio...

  18. Determination of Silicon in Gasoline by Directly Measuring under Organic Phase Using Inductively Coupled Plasma Optical Emission Spectroscopy.

    Science.gov (United States)

    Zhang, Wen-mei; Wen, Huan; Lü, Huan-ming; Liu, Hui-qin; Lin, Zhi-sheng; Wang, Rong-hua

    2015-03-01

    A simple and accurate method was developed for determining silicon in gasoline using inductively coupled plasma optical emission spectroscopy (ICP-OES). For sample inroduction a Burgener nubulizer and a Cyclonic spray chamber were used. A gasoline sample was diluted with isooctane and then introduced into the cooled spray chamber of the ICP-OES. Good linearity was achieved in the silicon concentration range 0.1 - 10.0 mg x kg(-1), and the correlation coefficient was 0.999 96. The detection limit for silicon was 0.012 mg x kg(-1) and the silicon recoveries from gasoline samples were 95.8% - 98.4%, with relative standard deviations of less than 3.0% The method was proved to be simple, reliable and highly sensitive, and suitable for determining silicon in samples of motor gasoline, ethanol-gasoline and methanol-gasoline fuel mixtures those containing not more than 15% (V/V) oxygenates.

  19. A study of internal oxidation in carburized steels by glow discharge optical emission spectroscopy and scanning electron microscopy

    CERN Document Server

    An, X; Rainforth, W M; Chen, L

    2003-01-01

    The internal oxidation of Cr-Mn carburizing steel was studied. Internal oxidation was induced using a commercial carburizing process. Sputter erosion coupled with glow discharge optical emission spectroscopy (GDOES) was used to determine the depth profile elemental distribution within the internal oxidation layer (<10 mu m). In addition, scanning electron microscopy (SEM) equipped with energy dispersive spectrometer (EDS) studies were carried out on selected sputter eroded surfaces. Oxide type was identified primarily by transmission electron microscopy (TEM). The carburized surface was found to consist of a continuous oxide layer, followed by a complex internal oxidation layer, where Cr and Mn oxides were found to populate grain boundaries in a globular form in the near surface region. At greater depths (5-10 mu m), Si oxides formed as a grain boundary network. The internal oxides (mainly complex oxides) grew quickly during the initial stages of the carburizing process (2 h, 800 deg. C+3 h, 930 deg. C). G...

  20. Aqueous solutions of uranium(VI) as studied by time-resolved emission spectroscopy: a round-robin test.

    Science.gov (United States)

    Billard, Isabelle; Ansoborlo, Eric; Apperson, Kathleen; Arpigny, Sylvie; Azenha, M Emilia; Birch, David; Bros, Pascal; Burrows, Hugh D; Choppin, Gregory; Couston, Laurent; Dubois, Veronique; Fanghänel, Thomas; Geipel, Gerhard; Hubert, Solange; Kim, Jae I; Kimura, Takaumi; Klenze, Reinhardt; Kronenberg, Andreas; Kumke, Michael; Lagarde, Gerard; Lamarque, Gerard; Lis, Stefan; Madic, Charles; Meinrath, Gunther; Moulin, Christophe; Nagaishi, Ryuji; Parker, David; Plancque, Gabriel; Scherbaum, Franz; Simoni, Eric; Sinkov, Sergei; Viallesoubranne, Carole

    2003-08-01

    Results of an inter-laboratory round-robin study of the application of time-resolved emission spectroscopy (TRES) to the speciation of uranium(VI) in aqueous media are presented. The round-robin study involved 13 independent laboratories, using various instrumentation and data analysis methods. Samples were prepared based on appropriate speciation diagrams and, in general, were found to be chemically stable for at least six months. Four different types of aqueous uranyl solutions were studied: (1) acidic medium where UO2(2+)aq is the single emitting species, (2) uranyl in the presence of fluoride ions, (3) uranyl in the presence of sulfate ions, and (4) uranyl in aqueous solutions at different pH, promoting the formation of hydrolyzed species. Results between the laboratories are compared in terms of the number of decay components, luminescence lifetimes, and spectral band positions. The successes and limitations of TRES in uranyl analysis and speciation in aqueous solutions are discussed.

  1. Band Gap Energy of Chalcopyrite Thin Film Solar Cell Absorbers Determined by Soft X-Ray Emission and Absorption Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Bar, M.; Weinhardt, L.; Pookpanratana, S.; Heske, C.; Nishiwaki, S.; Shafarman, W.; Fuchs, O.; Blum, M.; Yang, W.; Denlinger, J.D.

    2008-05-11

    The chemical and electronic structure of high efficiency chalcopyrite thin film solar cell absorbers significantly differs between the surface and the bulk. While it is widely accepted that the absorber surface exhibits a Cu-poor surface phase with increased band gap (Eg), a direct access to the crucial information of the depth-dependency of Eg is still missing. In this paper, we demonstrate that a combination of x-ray emission and absorption spectroscopy allows a determination of Eg in the surface-near bulk and thus complements the established surface- and bulk-sensitive techniques of Eg determination. As an example, we discuss the determination of Eg for a Cu(In,Ga)Se2 absorber [(1.52 +- 0.20) eV].

  2. Electronic structure of multiferroic BiFeO3 by resonant soft-x-ray emission spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Higuchi, Tohru; Higuchi, T.; Liu, Y.-S.; Yao, P.; Glans, P.-A.; Guo, Jinghua; Chang, C.; Wu, Z.; Sakamoto, W.; Itoh, N.; Shimura, T.; Yogo, T.; Hattori, T.

    2008-07-11

    The electronic structure of multiferroic BiFeO{sub 3} has been studied using soft-X-ray emission spectroscopy. The fluorescence spectra exhibit that the valence band is mainly composed of O 2p state hybridized with Fe 3d state. The band gap corresponding to the energy separation between the top of the O 2p valence band and the bottom of the Fe 3d conduction band is 1.3 eV. The soft-X-ray Raman scattering reflects the features due to charge transfer transition from O 2p valence band to Fe 3d conduction band. These findings are similar to the result of electronic structure calculation by density functional theory within the local spin-density approximation that included the effect of Coulomb repulsion between localized d states.

  3. Emission Mössbauer spectroscopy study of fluence dependence of paramagnetic relaxation in Mn/Fe implanted ZnO

    Science.gov (United States)

    Masenda, H.; Geburt, S.; Bharuth-Ram, K.; Naidoo, D.; Gunnlaugsson, H. P.; Johnston, K.; Mantovan, R.; Mølholt, T. E.; Ncube, M.; Shayestehaminzadeh, S.; Gislason, H. P.; Langouche, G.; Ólafsson, S.; Ronning, C.

    2016-12-01

    Emission Mössbauer Spectroscopy following the implantation of radioactive precursor isotope 57Mn+ ( T 1/2= 1.5 min) into ZnO single crystals at ISOLDE/CERN shows that a large fraction of 57Fe atoms produced in the 57Mn beta decay is created as paramagnetic Fe3+ with relatively long spin-lattice relaxation times. Here we report on ZnO pre-implanted with 56Fe to fluences of 2×1013, 5×10 13 and 8 × 1013 ions/cm2 in order to investigate the dependence of the paramagnetic relaxation rate of Fe3+ on fluence. The spectra are dominated by magnetic features displaying paramagnetic relaxation effects. The extracted spin-lattice relaxation rates show a slight increase with increasing ion fluence at corresponding temperatures and the area fraction of Fe3+ at room temperature reaches a maximum contribution of 80(3)% in the studied fluence range.

  4. Zinc, lead and copper in human teeth measured by induced coupled argon plasma atomic emission spectroscopy (ICP-AES)

    Energy Technology Data Exchange (ETDEWEB)

    Chew, L.T.; Bradley, D.A. E-mail: D.A.Bradley@exeter.ac.uk; Mohd, Y.; Jamil, M

    2000-11-15

    Inductively Coupled Argon Plasma Atomic Emission Spectroscopy (ICP-AES) has been used to determine Pb, Zn and Cu levels in 47 exfoliated human teeth (all of which required extraction for orthodontic reasons). Lead concentrations for the group were 1.7 {mu}g (g tooth mass){sup -1} to 40.5 {mu}g (g tooth mass){sup -1}, with a median of 9.8 {mu}g (g tooth mass){sup -1}. A median lead level in excess of the group value was found for the teeth of six lorry drivers who were included in the study. A more significant enhancement was found for the seven subjects whose age was in excess of 60 years. The median values for Zn and Cu were 123.0 and 0.6 {mu}g (g tooth mass){sup -1} respectively. Present values for tooth-Zn are lower than published data for other ethnic groups.

  5. Measurement of the scalar polarizability of the indium $6p_{1/2}$ state using two-step atomic-beam spectroscopy

    CERN Document Server

    Augenbraun, Benjamin L; Rupasinghe, P M; Majumder, P K

    2016-01-01

    We have completed a measurement of the Stark shift within the $^{115}$In $6s_{1/2} \\rightarrow 6p_{1/2}$ excited-state transition using two-step laser spectroscopy in an indium atomic beam. Combining this measurement with recent experimental results we determine the scalar polarizability, $\\alpha_{0}$, of the $6p_{1/2}$ state to be $7683 \\pm43 \\,a_{0}^{3}$ in atomic units, a result which agrees very well with recent theoretical calculations. In this experiment, one laser, stabilized to the $5p_{1/2} \\rightarrow 6s_{1/2}$ 410~nm transition, was directed transversely to the atomic beam, while a second, overlapping laser was scanned across the 1343~nm $6s_{1/2} \\rightarrow 6p_{1/2}$ transition. We utilized two-tone frequency-modulation spectroscopy of the infrared laser beam to measure the second-step absorption in the interaction region, where the optical depth is less than 10$^{-3}$. In the course of our experimental work we also determined the hyperfine splitting within the $6p_{1/2}$ state, improving upon th...

  6. Adsorption, X-ray Diffraction, Photoelectron, and Atomic Emission Spectroscopy Benchmark Studies for the Eighth Industrial Fluid Properties Simulation Challenge*+

    Science.gov (United States)

    Ross, Richard B.; Aeschliman, David B.; Ahmad, Riaz; Brennan, John K.; Brostrom, Myles L.; Frankel, Kevin A.; Moore, Jonathan D.; Moore, Joshua D.; Mountain, Raymond D.; Poirier, Derrick M.; Thommes, Matthias; Shen, Vincent K.; Schultz, Nathan E.; Siderius, Daniel W.; Smith, Kenneth D.

    2016-01-01

    The primary goal of the eighth industrial fluid properties simulation challenge was to test the ability of molecular simulation methods to predict the adsorption of organic adsorbates in activated carbon materials. The challenge focused on the adsorption of perfluorohexane in the activated carbon standard BAM-P109 (Panne and Thünemann 2010). Entrants were challenged to predict the adsorption of perfluorohexane in the activated carbon at a temperature of 273 K and at relative pressures of 0.1, 0.3, and 0.6. The relative pressure (P/Po) is defined as that relative to the bulk saturation pressure predicted by the fluid model at a given temperature (273 K in this case). The predictions were judged by comparison to a set of experimentally determined values, which are published here for the first time and were not disclosed to the entrants prior to the challenge. Benchmark experimental studies, described herein, were also carried out and provided to entrants in order to aid in the development of new force fields and simulation methods to be employed in the challenge. These studies included argon, carbon dioxide, and water adsorption in the BAM-P109 activated carbon as well as X-ray diffraction, X-ray microtomography, photoelectron spectroscopy, and atomic emission spectroscopy studies of BAM-P109. Several concurrent studies were carried out for the BAM-P108 activated carbon (Panne and Thünemann 2010). These are included in the current manuscript for comparison. PMID:27840543

  7. Resonant x-ray emission spectroscopy of liquid water: novel instrumentation, high resolution, and the"map" approach

    Energy Technology Data Exchange (ETDEWEB)

    Weinhardt, L.; Fuchs, O.; Blum, M.; B& #228; r, M.; Weigand, M.; Denlinger, J.D.; Zubavichus, Y.; Zharnikov, M.; Grunze, M.; Heske, C.; Umbach, E.

    2008-06-17

    Techniques to study the electronic structure of liquids are rare. Most recently, resonant x-ray emission spectroscopy (XES) has been shown to be an extremely versatile spectroscopy to study both occupied and unoccupied electronic states for liquids in thermodynamic equilibrium. However, XES requires high-brilliance soft x-ray synchrotron radiation and poses significant technical challenges to maintain a liquid sample in an ultra-high vacuum environment. Our group has therefore developed and constructed a novel experimental setup for the study of liquids, with the long-term goal of investigating the electronic structure of biological systems in aqueous environments. We have developed a flow-through liquid cell in which the liquid is separated from vacuum by a thin Si3N4 or SiC window and which allows a precise control of temperature. This approach has significant advantages compared to static liquids cells used in the past. Furthermore, we have designed a dedicated high-transmission, high-resolution soft x-ray spectrometer. The high transmission makes it possible to measure complete resonant XES"maps" in less than an hour, giving unprecedented detailed insight into the electronic structure of the investigated sample. Using this new equipment we have investigated the electronic structure of liquid water. Furthermore, our XES spectra and maps give information about ultra-fast dissociation on the timescale of the O 1s core hole lifetime, which is strongly affected by the initial state hydrogen bonding configuration.

  8. X-ray emission spectroscopy applied to glycine adsorbed on Cu(110): An atom and symmetry projected view

    Energy Technology Data Exchange (ETDEWEB)

    Hasselstroem, J.; Karis, O.; Weinelt, M. [Uppsala Univ. (Sweden)] [and others

    1997-04-01

    When a molecule is adsorbed on a metal surface by chemical bonding new electronic states are formed. For noble and transition metals these adsorption-induced states overlap with the much more intense metal d-valence band, making them difficult to probe by for instance direct photoemission. However, it has recently been shown that X-ray emission spectroscopy (XES) can be applied to adsorbate systems. Since the intermediate state involves a core hole, this technique has the power to project out the partial density of states around each atomic site. Both the excitation and deexcitation processes are in general governed by the dipole selection rules. For oriented system, it is hence possible to obtain a complete separation into 2p{sub x}, 2p{sub y} and 2p{sub z} contributions using angular resolved measurements. The authors have applied XES together with other core level spectroscopies to glycine adsorption on Cu(110). Glycine (NH{sub 2}CH{sub 2}COOH) is the smallest amino acid and very suitable to study by core level spectroscopy since it has several functional groups, all well separated in energy by chemical shifts. Its properties are futhermore of biological interest. In summary, the authors have shown that it is possible to apply XES to more complicated molecular adsorbates. The assignment of different electronic states is however not as straight forward as for simple diatomic molecules. For a complete understanding of the redistribution and formation of new electronic states associated with the surface chemical bond, experimental data must be compared to theoretical calculations.

  9. Electrostatically focused addressable field emission array chips (AFEA's) for high-speed massively parallel maskless digital E-beam direct write lithography and scanning electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, Clarence E. (Knoxville, TN); Baylor, Larry R. (Farragut, TN); Voelkl, Edgar (Oak Ridge, TN); Simpson, Michael L. (Knoxville, TN); Paulus, Michael J. (Knoxville, TN); Lowndes, Douglas H. (Knoxville, TN); Whealton, John H. (Oak Ridge, TN); Whitson, John C. (Clinton, TN); Wilgen, John B. (Oak Ridge, TN)

    2002-12-24

    Systems and methods are described for addressable field emission array (AFEA) chips. A method of operating an addressable field-emission array, includes: generating a plurality of electron beams from a pluralitly of emitters that compose the addressable field-emission array; and focusing at least one of the plurality of electron beams with an on-chip electrostatic focusing stack. The systems and methods provide advantages including the avoidance of space-charge blow-up.

  10. Composition variations in Cu{sub 2}ZnSnSe{sub 4} thin films analyzed by X-ray diffraction, energy dispersive X-ray spectroscopy, particle induced X-ray emission, photoluminescence, and Raman spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Nam, Dahyun [Department of Physics, Sogang University, Seoul 121-742 (Korea, Republic of); Opanasyuk, A.S.; Koval, P.V.; Ponomarev, A.G. [Department of Electronics and Computer Technology, Sumy State University, Sumy UA-40007 (Ukraine); Jeong, Ah Reum; Kim, Gee Yeong; Jo, William [Department of Physics, Ewha Womans University, Seoul 120-750 (Korea, Republic of); Cheong, Hyeonsik, E-mail: hcheong@sogang.ac.kr [Department of Physics, Sogang University, Seoul 121-742 (Korea, Republic of)

    2014-07-01

    Compositional and structural studies of Cu{sub 2}ZnSnSe{sub 4} (CZTSe) thin films were carried out by X-ray diffraction, energy dispersive X-ray spectroscopy (EDS), particle induced X-ray emission (PIXE), photoluminescence, and Raman spectroscopy. CZTSe thin films with different compositions were deposited on sodalime glass by co-evaporation. The composition of the films measured by two different methods, EDS and PIXE, showed significant differences. Generally, the Zn/Sn ratio measured by EDS is larger than that measured by PIXE. Both the micro-PIXE and the micro-Raman imaging results indicated the compositional and structural inhomogeneity of the sample. - Highlights: • Particle induced X-ray emission was used to analyze the composition of CZTSe films. • Energy dispersive X-ray spectroscopy tends to underestimate the Sn composition. • Local Raman intensity is related with the composition rather than the crystallinity.

  11. Positron emission tomography for the dose monitoring of intra-fractionally moving targets in ion beam therapy

    Energy Technology Data Exchange (ETDEWEB)

    Stuetzer, Kristin

    2014-07-01

    Ion beam therapy (IBT) is a promising treatment option in radiotherapy. The characteristic physical and biological properties of light ion beams allow for the delivery of highly tumor conformal dose distributions. Related to the sparing of surrounding healthy tissue and nearby organs at risk, it is feasible to escalate the dose in the tumor volume to reach higher tumor control and survival rates. Remarkable clinical outcome was achieved with IBT for radio-resistant, deep-seated, static and well fixated tumor entities. Presumably, more patients could benefit from the advantages of IBT if it would be available for more frequent tumor sites. Those located in the thorax and upper abdominal region are commonly subjected to intra-fractional, respiration related motion. Different motion-compensated dose delivery techniques have been developed for active field shaping with scanned pencil beams and are at least available under experimental conditions at the GSI Helmholtzzentrum fuer Schwerionenforschung (GSI) in Darmstadt, Germany. Since minor unexpected anatomical changes e.g. related to patient mispositioning, tumour shrinkage or tissue swelling could already lead to remarkable deviations between planned and delivered dose distribution, a valuable dose monitoring system is desired for IBT. So far, positron emission tomography (PET) is the only in vivo, in situ and non-invasive qualitative dose monitoring method applied under clinical conditions. Conclusions about the delivered dose distribution can be drawn indirectly from a comparison between two β{sup +}-activity distributions: the measured one and an expected one generated by a Monte-Carlo simulation. Dedicated phantoms mainly made up of polymethyl methacrylate (PMMA) and a motion table for regular one-dimensional (1D) motion patterns have been designed and manufactured for the experiments. Furthermore, the general applicability of the 4D MLEM algorithm for more complex motion patterns has been demonstrated by the

  12. Evaluation of cross-sections for particle induced gamma-ray emission (PIGE) spectroscopy

    Science.gov (United States)

    Gurbich, A. F.

    2014-07-01

    The extension of the cross-section evaluation procedure to PIGE data was investigated and the first results are reported. Two different cases were studied: the gamma emission accompanying inelastic scattering of protons, and the (p,γ)-reaction. The corresponding theoretical calculations were performed in the framework of R-matrix and DWBA for the (p,p‧γ) reaction on 23Na, and using statistical model for the proton radiative capture by 52Cr. The possibility of achieving a close fit to the experimental data is demonstrated.

  13. Evaluation of cross-sections for particle induced gamma-ray emission (PIGE) spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Gurbich, A.F., E-mail: gurbich@ippe.ru

    2014-07-15

    The extension of the cross-section evaluation procedure to PIGE data was investigated and the first results are reported. Two different cases were studied: the gamma emission accompanying inelastic scattering of protons, and the (p,γ)-reaction. The corresponding theoretical calculations were performed in the framework of R-matrix and DWBA for the (p,p′γ) reaction on {sup 23}Na, and using statistical model for the proton radiative capture by {sup 52}Cr. The possibility of achieving a close fit to the experimental data is demonstrated.

  14. Determination of phosphorus in lubricating oils by cool-flame emission spectroscopy.

    Science.gov (United States)

    Elliott, W N; Heathcote, C; Mostyn, R A

    1972-03-01

    The phosphorus content of lubricating oils is determined by measurement of the emission from the HPO molecular species at 528 nm in a cool hydrogen-nitrogen diffusion flame. The oil is ashed in the presence of potassium hydroxide and an aqueous extract of the melt is treated with ion-exchange resin to remove interferents, before aspiration into the flame. Analytical results are presented on samples containing phosphorus in the range 0.009-0.2%. The precision of the method is +/- 5% at the 0.04% phosphorus level.

  15. Inductively Coupled Plasma Optical-Emission Spectroscopy Determination of Major and Minor Elements in Vinegar

    Directory of Open Access Journals (Sweden)

    Arzu AKPINAR-BAYIZIT

    2010-12-01

    Full Text Available This study characterizes the mineral content of vinegar samples. The concentrations of Na, K, Ca, Mg and P (major elements as well as Fe, Mn, Sn, Cu, Ni, Zn, Pb and Cd (minor elements were determined in 35 commercial vinegar samples using inductively coupled plasma optical-emission spectrometry (ICP-OES. The elements with the highest concentrations were K, Na, Ca, Mg and P. The concentrations of heavy metals in the vinegar samples, including Cd, Ni, Sn and Pb, were not considered a health risk.

  16. Chemical Analysis of Impurity Boron Atoms in Diamond Using Soft X-ray Emission Spectroscopy

    OpenAIRE

    Muramatsu, Yasuji

    2009-01-01

    To analyze the local structure and/or chemical states of boron atoms in boron-doped diamond, which can be synthesized by the microwave plasma-assisted chemical vapor deposition method (CVD-B-diamond) and the temperature gradient method at high pressure and high temperature (HPT-B-diamond), we measured the soft X-ray emission spectra in the CK and BK regions of B-diamonds using synchrotron radiation at the Advanced Light Source (ALS). X-ray spectral analyses using the fingerprint method and mo...

  17. Comparison Between X-rays Absorption and Emission Spectroscopy Measurements on a Ceramic Envelop Lamp

    Institute of Scientific and Technical Information of China (English)

    Bruno LAFITTE; Michel AUBES; Georges ZISSIS

    2007-01-01

    Burners of metal halide lamps used for illumination are generally made of polycrystalline alumina ceramic (PCA) which is translucent to visible light.We show that the difficulty of selecting a line of sight through the lamp prevents the use of optical emission diagnostic.X-rays photons are mainly absorbed and not scattered by PCA.Absorption by mercury atoms contributing to the discharge allowed us to determine the density of mercury in the lamp.By comparing diagnostic methods,we put in evidence the difficulty of taking into account the scattering of light mathematically.

  18. Atmospheric Longwave Infrared Emission Spectroscopy of Water Vapor at the South Pole

    OpenAIRE

    Myers, Brooke A.

    2000-01-01

    The downward infrared radiance spectrum was measured with a Michelson Long Wave Infrared (LWIR) spectrometer at the Amundsen-Scott South Pole Station. Spectra were collected year-round at the South Pole in 1998. This research focuses on the atmospheric water emission lines between 250 and 800 cm-1 (40 to 12.5 μm) region. The spectral resolution is 1 cm-1. The atmosphere over the South Pole is the driest and coldest on Earth. Winter surface temperatures average approximately -60°C, while the t...

  19. X-ray and TeV Gamma-Ray Emission from Parallel Electron-Positron or Electron-Proton Beams in BL Lac Objects

    CERN Document Server

    Krawczynski, H

    2006-01-01

    In this paper we discuss models of the X-rays and TeV gamma-ray emission from BL Lac objects based on parallel electron-positron or electron-proton beams that form close to the central black hole owing to the strong electric fields generated by the accretion disk and possibly also by the black hole itself. Fitting the energy spectrum of the BL Lac object Mrk 501, we obtain tight constrains on the beam properties. Launching a sufficiently energetic beam requires rather strong magnetic fields close to the black hole 100-1000 G. However, the model fits imply that the magnetic field in the emission region is only 0.02 G. Thus, the particles are accelerated close to the black hole and propagate a considerable distance before instabilities trigger the dissipation of energy through synchrotron and self-Compton emission. We discuss various approaches to generate enough power to drive the jet and, at the same time, to accelerate particles to 20 TeV energies. Although the parallel beam model has its own problems, it ex...

  20. X-Ray and TeV Gamma-Ray Emission from Parallel Electron-Positron or Electron-Proton Beams in BL Lacertae Objects

    Science.gov (United States)

    Krawczynski, H.

    2007-04-01

    In this paper we discuss models of the X-ray and TeV γ-ray emission from BL Lac objects based on parallel electron-positron or electron-proton beams that form close to the central black hole, due to the strong electric fields generated by the accretion disk and possibly also by the black hole itself. Fitting the energy spectrum of the BL Lac object Mrk 501, we obtain tight constraints on the beam properties. Launching a sufficiently energetic beam requires rather strong magnetic fields close to the black hole (~100-1000 G). However, the model fits imply that the magnetic field in the emission region is only ~0.02 G. Thus, the particles are accelerated close to the black hole and propagate a considerable distance before instabilities trigger the dissipation of energy through synchrotron and self-Compton emission. We discuss various approaches to generate enough power to drive the jet and, at the same time, to accelerate particles to ~20 TeV energies. Although the parallel beam model has its own problems, it explains some of the long-standing problems that plague models based on Fermi-type particle acceleration, such as the presence of a very high minimum Lorentz factor of accelerated particles. We conclude with a brief discussion of the implications of the model for the difference between the processes of jet formation in BL Lac-type objects and those in quasars.

  1. X-ray and TeV Gamma-Ray Emission from Parallel Electron-Positron or Electron-Proton Beams in BL Lac Objects

    Science.gov (United States)

    Krawczynski, Henric

    2007-04-01

    In this contribution we discuss models of the X-rays and TeV gamma-ray emission from BL Lac objects based on parallel electron-positron or electron-proton beams that form close to the central black hole owing to the strong electric fields generated by the accretion disk and possibly also by the black hole itself. Fitting the energy spectrum of the BL Lac object Mrk 501, we obtain tight constrains on the beam properties. Launching a sufficiently energetic beam requires rather strong magnetic fields close to the black hole 100-1000 G. However, the model fits imply that the magnetic field in the emission region is only 0.02 G. Thus, the particles are accelerated close to the black hole and propagate a considerable distance before instabilities trigger the dissipation of energy through synchrotron and self-Compton emission. We discuss various approaches to generate enough power to drive the jet and, at the same time, to accelerate particles to 20 TeV energies. Although the parallel beam model has its own problems, it explains some of the long-standing problems that plague models based on Fermi type particle acceleration, like the presence of a very high minimum Lorentz factor of accelerated particles. We conclude with a brief discussion of the implications of the model for the difference between the processes of jet formation in BL Lac type objects and in quasars.

  2. Characterization of direct current He-N{sub 2} mixture plasma using optical emission spectroscopy and mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Flores, O.; Castillo, F.; Martinez, H. [Laboratorio de Espectroscopia, Instituto de Ciencias Físicas, Universidad Nacional Autónoma de México, Apartado Postal 48-3, 62251, Cuernavaca, Morelos (Mexico); Villa, M.; Reyes, P. G. [Facultad de Ciencias, Universidad Autónoma del Estado de México, Estado de México (Mexico); Villalobos, S. [Laboratorio de Espectroscopia, Instituto de Ciencias Físicas, Universidad Nacional Autónoma de México, Apartado Postal 48-3, 62251, Cuernavaca, Morelos (Mexico); Facultad de Ingeniería, Universidad Nacional Autónoma de México, México D.F. (Mexico)

    2014-05-15

    This study analyses the glow discharge of He and N{sub 2} mixture at the pressure of 2.0 Torr, power of 10 W, and flow rate of 16.5 l/min, by using optical emission spectroscopy and mass spectrometry. The emission bands were measured in the wavelength range of 200–1100 nm. The principal species observed were N{sub 2}{sup +} (B{sup 2}Σ{sup +}{sub u}→X{sup 2}Σ{sup +}{sub g}), N{sub 2} (C{sup 3}Π{sub u}→B{sup 3}Π{sub g}), and He, which are in good agreement with the results of mass spectrometry. Besides, the electron temperature and ion density were determined by using a double Langmuir probe. Results indicate that the electron temperature is in the range of 1.55–2.93 eV, and the electron concentration is of the order of 10{sup 10} cm{sup −3}. The experimental results of electron temperature and ion density for pure N{sub 2} and pure He are in good agreement with the values reported in the literature.

  3. Physical Properties of Emission-Line Galaxies at z ~ 2 from Near-Infrared Spectroscopy with Magellan FIRE

    CERN Document Server

    Masters, Daniel; Siana, Brian; Malkan, Matthew; Mobasher, Bahram; Atek, Hakim; Henry, Alaina; Martin, Crystal L; Rafelski, Marc; Hathi, Nimish P; Scarlata, Claudia; Ross, Nathaniel R; Bunker, Andrew J; Blanc, Guillermo A; Bedregal, Alejandro G; Dominguez, Alberto; Colbert, James; Teplitz, Harry; Dressler, Alan

    2014-01-01

    We present results from near-infrared spectroscopy of 26 emission-line galaxies at z ~ 2 obtained with the FIRE spectrometer on the Magellan Baade telescope. The sample was selected from the WISP survey, which uses the near-infrared grism of the Hubble Space Telescope Wide Field Camera 3 to detect emission-line galaxies over 0.3 1 star-forming galaxies, but composite spectra derived from the sample do not show an appreciable offset from the local star-forming sequence on the [O III]/H-beta versus [S II]/H-alpha diagram. We infer a high nitrogen-to-oxygen abundance ratio from the composite spectrum, which may contribute to the offset of the high-redshift galaxies from the local star-forming sequence in the [O III]/H-beta versus [N II]/H-alpha diagram. We speculate that the elevated nitrogen abundance could result from substantial numbers of Wolf-Rayet stars in starbursting galaxies at z~2. (Abridged)

  4. Further evidence for charge transfer complexes in brown carbon aerosols from excitation-emission matrix fluorescence spectroscopy.

    Science.gov (United States)

    Phillips, Sabrina M; Smith, Geoffrey D

    2015-05-14

    The light-absorbing fraction of organic molecules in ambient aerosols, known as "brown carbon," is an important yet poorly characterized component. Despite the fact that brown carbon could alter the radiative forcing of aerosols significantly, identification of specific chromophores has remained challenging. We recently demonstrated that charge transfer (CT) complexes formed in organic molecules could be responsible for a large fraction of absorption observed in water-extracted ambient particulate matter.1 In the present study, we use excitation-emission matrix fluorescence spectroscopy to further corroborate the importance of CT complexes in defining aerosol optical properties. Monotonically increasing and decreasing quantum yields, decreasing Stokes shifts, and red-shifting emission maxima are observed from ambient particulate matter collected in Athens, Georgia, strongly suggesting that a superposition of independent chromophores is not sufficient to explain brown carbon absorption and fluorescence. Instead, we show that a model in which such chromophores are energetically coupled to a dense manifold of CT complexes is consistent with all of the observations. Further, we suggest that a significant fraction of the observed fluorescence originates from CT complexes and that their contribution to brown carbon absorption is likely greater than we reported previously.

  5. The Nature of Extreme Emission Line Galaxies at z=1-2: Kinematics and Metallicities from Near-Infrared Spectroscopy

    CERN Document Server

    Maseda, Michael V; Rix, Hans-Walter; da Cunha, Elisabete; Pacifici, Camilla; Momcheva, Ivelina; Brammer, Gabriel B; Meidt, Sharon E; Franx, Marijn; van Dokkum, Pieter; Fumagalli, Mattia; Bell, Eric F; Ferguson, Henry C; Förster-Schreiber, Natascha M; Koekemoer, Anton M; Koo, David C; Lundgren, Britt F; Marchesini, Danilo; Nelson, Erica J; Patel, Shannon G; Skelton, Rosalind E; Straughn, Amber N; Trump, Jonathan R; Whitaker, Katherine E

    2014-01-01

    We present near-infrared spectroscopy of a sample of 22 Extreme Emission Line Galaxies at redshifts 1.3 5) and [N II]/H{\\alpha} is always significantly below unity, which suggests a low gas-phase metallicity. We are able to determine gas-phase metallicities for 7 of our objects using various strong-line methods, with values in the range 0.05-0.30 Z_sun and with a median of 0.15 Z_sun; for 3 of these objects we detect [O III]{\\lambda}4363 which allows for a direct constraint on the metallicity. The velocity dispersion, as measured from the nebular emission lines, is typically ~50 km/s. Combined with the observed star-forming activity, the Jeans and Toomre stability criteria imply that the gas fraction must be large (> 2/3), consistent with the difference between our dynamical and stellar mass estimates. The implied gas depletion time scale (several hundred Myr) is substantially longer than the inferred mass-weighted ages (~50 Myr), which further supports the emerging picture that most stars in low-mass galaxi...

  6. Spectroscopy of southern Galactic disk planetary nebulae. Notes on chemical composition and emission-line stars

    CERN Document Server

    Górny, S K

    2014-01-01

    We present low resolution spectroscopic observations for a sample of 53 planetary nebulae (PNe) located in the southern sky between Vela and Norma constellations and pertaining to the Galactic disk with expected Galactocentric distance range of 5 to 10 kpc. We derive nebular chemical composition and plasma parameters with the classical empirical method. For most of the observed objects it is done for the first time. The distributions of the chemical abundances of the observed disk sample are generally indistinguishable from Galactic bulge and inner-disk PNe populations. The exceptions are possible differences in He/H distribution comparing to bulge PNe and Ne/Ar comparing to inner-disk PNe sample. The derived O/H ratios for the observed disk PNe fit to the concept of flattening of the chemical gradient in the inner parts of the Milky Way. We use the spectra to search for emission-line central stars in the observed sample. We found 6 new emission-line central stars comprising examples of all known types: WEL, ...

  7. IFU Spectroscopy of 10 ETG nuclei: Properties of the circumnuclear gas emission

    Science.gov (United States)

    Ricci, T. V.

    2015-09-01

    LINERs are galactic nuclei containing spectra with prominence of low-ionization lines. Several ionization sources are able to produce a LINER-like spectra (e.g. shocks, low-luminosity AGNs, pAGB stars). In this work, we will present an analysis performed on a sample of 10 massive ETGs with distances up to 30 Mpc. This sample was observed with the GMOS-IFU installed on the Gemini-South Telescope. The data cubes of the galaxies have a FOV of 3.5 - 5 arcsec2 and a spatial resolution of about 0.6 -- 1.0 arcsec. After subtracting the stellar component of the galaxies by means of spectral synthesis, we studied the emission lines all over the FOV of the data cubes. In galaxies where an AGN was clearly detected, we found ionized gaseous discs and also a low-velocity extended emission perpendicular to the gas discs. We concluded that only ionizing photons emerging from the AGNs are not enough to photoionize the gaseous discs of the galaxies. On the other hand, it seems to be responsible for the photoionization of the low-velocity extended gas perpendicular to the discs. We propose a scheme where some collimating agent, somehow aligned to the gaseous discs, may be present in some LINER-like AGNs in the local universe.

  8. Suzaku Spectroscopy Study of Hard X-Ray Emission in the Arches Cluster

    CERN Document Server

    Tsujimoto, M; Koyama, K

    2006-01-01

    We present the results of a Suzaku study of the Arches cluster. A high S/N spectrum in the 3-12 keV band was obtained with the XIS. We found that the spectrum consists of a thermal plasma, a hard power-law tail, and two Gaussian lines. The plasma component (kT~2.2 keV) is established from the presence of CaXIX and FeXXV K alpha lines as well as the absence of FeXXVI K alpha line. The two Gaussian lines represent the K alpha and beta lines from iron at lower ionization stages. Both the line centers and the intensity ratio of these two lines are consistent with the neutral iron. The hard power-law tail (index~0.7) was found to have no pronounced iron K edge feature. In comparison with the published Chandra spectra, we conclude that the thermal component is from the ensemble of point-like sources plus thermal diffuse emission concentrated at the cluster center, while the Gaussian and the hard tail components are from the non-thermal diffuse emission extended in a larger scale. In the band-limited XIS images, the...

  9. Glow discharge optical emission spectroscopy for accurate and well resolved analysis of coatings and thin films

    KAUST Repository

    Wilke, Marcus

    2011-12-01

    In the last years, glow discharge optical emission spectrometry (GDOES) gained more and more acceptance in the analysis of functional coatings. GDOES thereby represents an interesting alternative to common depth profiling techniques like AES and SIMS, based on its unique combination of high erosion rates and erosion depths, sensitivity, analysis of nonconductive layers and easy quantification even for light elements such as C, N, O and H. Starting with the fundamentals of GDOES, a short overview on new developments in instrument design for accurate and well resolved thin film analyses is presented. The article focuses on the analytical capabilities of glow discharge optical emission spectrometry in the analysis of metallic coatings and thin films. Results illustrating the high depth resolution, confirmation of stoichiometry, the detection of light elements in coatings as well as contamination on the surface or interfaces will be demonstrated by measurements of: a multilayer system Cr/Ti on silicon, interface contamination on silicon during deposition of aluminum, Al2O3-nanoparticle containing conversion coatings on zinc for corrosion resistance, Ti3SiC2 MAX-phase coatings by pulsed laser deposition and hydrogen detection in a V/Fe multilayer system. The selected examples illustrate that GDOES can be successfully adopted as an analytical tool in the development of new materials and coatings. A discussion of the results as well as of the limitations of GDOES is presented. © 2011 Elsevier B.V.

  10. Field emission spectroscopy evidence for dual-barrier electron tunnelling in nanographite

    Energy Technology Data Exchange (ETDEWEB)

    Bandurin, D. A.; Kleshch, V. I. [Department of Physics, M.V. Lomonosov Moscow State University, Moscow 119991 (Russian Federation); Mingels, S.; Lützenkirchen-Hecht, D.; Müller, G. [FB C Physics Department, University of Wuppertal, 42119 Wuppertal (Germany); Obraztsov, A. N., E-mail: obraz@polly.phys.msu.ru [Department of Physics, M.V. Lomonosov Moscow State University, Moscow 119991 (Russian Federation); Department of Physics and Mathematics, University of Eastern Finland, Joensuu 80101 (Finland)

    2015-06-08

    Nanocarbon films with upstanding flake-like graphite crystallites of nanometre thickness were fabricated by carbon condensation from a methane–hydrogen gas mixture activated by a direct-current discharge. The nanographite (NG) crystallites are composed of a few graphene layers. The adjacent atomic layers are connected partially at the edges of the crystallites to form strongly curved graphene structures. The extraordinary field emission (FE) properties were revealed for the NG films with an average current density of a few mA/cm{sup 2}, reproducibly obtained at a macroscopic applied field of about 1 V/μm. The integral FE current–voltage curves and electron spectra (FEES) of NG cathodes with multiple emitters were measured in a triode configuration. Most remarkably, above a threshold field, two peaks were revealed in FEES with different field-dependent shifts to lower energies. This behaviour evidences electron emission through a dual potential barrier, corresponding to carbon–carbon heterostructure formed as a result of the graphene bending.

  11. Watching adsorption and electron beam induced decomposition on the model system Mo(CO){sub 6}/Cu(1 1 1) by X-ray absorption and photoemission spectroscopies

    Energy Technology Data Exchange (ETDEWEB)

    Paufert, Pierre, E-mail: pierre.paufert@u-bourgogne.fr [ICB, UMR 6303 CNRS-Université de Bourgogne, BP 47870, 21078 Dijon cedex (France); Fonda, Emiliano [Synchrotron SOLEIL, BP48, St Aubin, 91192 Gif sur Yvette cedex (France); Li, Zheshen [ISA, University of Aarhus, Ny Munkegade, DK-8000 Aarhus C (Denmark); Domenichini, Bruno, E-mail: bruno.domenichini@u-bourgogne.fr [ICB, UMR 6303 CNRS-Université de Bourgogne, BP 47870, 21078 Dijon cedex (France); Bourgeois, Sylvie [ICB, UMR 6303 CNRS-Université de Bourgogne, BP 47870, 21078 Dijon cedex (France)

    2013-11-01

    An in-depth study of the first steps of electron beam assisted growth of Mo from molybdenum hexacarbonyl on Cu(1 1 1) has been carried out exploiting the complementarity of X-ray photoemission and X-ray absorption spectroscopies. Frank van der Merwe (2D) growth mode has been observed for the completion of the two first monolayers of adsorbed molecules through a simple physisorption process. Irradiation of the Mo(CO){sub 6} deposit by 1 keV electron beam induces a modification of molybdenum coordination, the average number of C-neighbors decreasing from 6 to 3. Decomposed molecules remain on the surface after annealing at 520 K and organize themselves, the molybdenum atoms moving in Cu(1 1 1) surface fcc hollow sites. After annealing at 670 K, metallic molybdenum growth begins, if the total amount of adsorbed Mo atoms exceeds 1.2 monolayers.

  12. Watching adsorption and electron beam induced decomposition on the model system Mo(CO)6/Cu(1 1 1) by X-ray absorption and photoemission spectroscopies

    Science.gov (United States)

    Paufert, Pierre; Fonda, Emiliano; Li, Zheshen; Domenichini, Bruno; Bourgeois, Sylvie

    2013-11-01

    An in-depth study of the first steps of electron beam assisted growth of Mo from molybdenum hexacarbonyl on Cu(1 1 1) has been carried out exploiting the complementarity of X-ray photoemission and X-ray absorption spectroscopies. Frank van der Merwe (2D) growth mode has been observed for the completion of the two first monolayers of adsorbed molecules through a simple physisorption process. Irradiation of the Mo(CO)6 deposit by 1 keV electron beam induces a modification of molybdenum coordination, the average number of C-neighbors decreasing from 6 to 3. Decomposed molecules remain on the surface after annealing at 520 K and organize themselves, the molybdenum atoms moving in Cu(1 1 1) surface fcc hollow sites. After annealing at 670 K, metallic molybdenum growth begins, if the total amount of adsorbed Mo atoms exceeds 1.2 monolayers.

  13. OH concentration in an atmospheric-pressure methane-air flame from molecular-beam mass spectrometry and laser-absorption spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Cattolica, R.J.; Yoon, S.; Knuth, E.L.

    1980-12-01

    The concentration of the OH radical in a stoichiometric methane-air flat flame at atmospheric pressure was measured with both laser-absorption spectroscopy and molecular-beam mass spectrometry (MBMS). The nonequilibrium peak OH concentrations and the OH decay rate measured from the two techniques were in good agreement. The OH profile from the MBMS measurements, however, was shifted downstream from the absorption measurements by approximately 5 times the sampling-orifice diameter. A comparison of temperature profiles from thermocouple measurements and from a molecular-beam time-of-flight technique exhibited a similar downstream shift. The MBMS measurements effectively sampled the gas properties approximately five orifice diameters ahead of the sampling-probe tip. Perturbation of the OH concentration profile using various sampling probes indicate the importance of minimizing the length of the sampling-orifice channel to reduce composition relaxation during sampling.

  14. Investigation of local thermodynamic equilibrium of laser induced Al2O3–TiC plasma in argon by spatially resolved optical emission spectroscopy

    Directory of Open Access Journals (Sweden)

    K. Alnama

    2016-06-01

    Full Text Available Plasma plume of Al2O3–TiC is generated by third harmonic Q-switched Nd:YAG nanosecond laser. It is characterized using Optical Emission Spectroscopy (OES at different argon background gas pressures 10, 102, 103, 104 and 105 Pa. Spatial evolution of excitation and ionic temperatures is deduced from spectral data analysis. Temporal evolution of Ti I emission originated from different energy states is probed. The correlation between the temporal behavior and the spatial temperature evolution are investigated under LTE condition for the possibility to use the temporal profile of Ti I emission as an indicator for LTE validity in the plasma.

  15. Investigation of local thermodynamic equilibrium of laser induced Al2O3-TiC plasma in argon by spatially resolved optical emission spectroscopy

    Science.gov (United States)

    Alnama, K.; Alkhawwam, A.; Jazmati, A. K.

    2016-06-01

    Plasma plume of Al2O3-TiC is generated by third harmonic Q-switched Nd:YAG nanosecond laser. It is characterized using Optical Emission Spectroscopy (OES) at different argon background gas pressures 10, 102, 103, 104 and 105 Pa. Spatial evolution of excitation and ionic temperatures is deduced from spectral data analysis. Temporal evolution of Ti I emission originated from different energy states is probed. The correlation between the temporal behavior and the spatial temperature evolution are investigated under LTE condition for the possibility to use the temporal profile of Ti I emission as an indicator for LTE validity in the plasma.

  16. Matrix formalism for calculation of the light beam intensity in stratified multilayered films, and its use in the analysis of emission spectra.

    Science.gov (United States)

    Ohta, K; Ishida, H

    1990-06-01

    Matrix formulation to describe the light propagation in stratified multilayered films has been extended to a system with phase incoherence. Several equations for the reflectance, transmittance, and light beam intensity in the film system are derived from the formulation. Some formulas previously proposed are corrected in reference to the present method. The beam intensity description is used for the calculation of light emissive power from multilayered films having a temperature gradient. It is found that the equations derived here are exactly equivalent to those derived from the radiative transfer equation. However, the present method is more tractable, and can be readily used for a film system with any number of layers.

  17. Assessing electron beam sensitivity for SrTiO3 and La0.7Sr0.3MnO3 using electron energy loss spectroscopy.

    Science.gov (United States)

    Nord, Magnus; Vullum, Per Erik; Hallsteinsen, Ingrid; Tybell, Thomas; Holmestad, Randi

    2016-10-01

    Thresholds for beam damage have been assessed for La0.7Sr0.3MnO3 and SrTiO3 as a function of electron probe current and exposure time at 80 and 200kV acceleration voltage. The materials were exposed to an intense electron probe by aberration corrected scanning transmission electron microscopy (STEM) with simultaneous acquisition of electron energy loss spectroscopy (EELS) data. Electron beam damage was identified by changes of the core loss fine structure after quantification by a refined and improved model based approach. At 200kV acceleration voltage, damage in SrTiO3 was identified by changes both in the EEL fine structure and by contrast changes in the STEM images. However, the changes in the STEM image contrast as introduced by minor damage can be difficult to detect under several common experimental conditions. No damage was observed in SrTiO3 at 80kV acceleration voltage, independent of probe current and exposure time. In La0.7Sr0.3MnO3, beam damage was observed at both 80 and 200kV acceleration voltages. This damage was observed by large changes in the EEL fine structure, but not by any detectable changes in the STEM images. The typical method to validate if damage has been introduced during acquisitions is to compare STEM images prior to and after spectroscopy. Quantifications in this work show that this method possibly can result in misinterpretation of beam damage as changes of material properties.

  18. Resonant X-ray emission spectroscopy reveals d-d ligand-field states involved in the self-assembly of a square-planar platinum complex.

    Science.gov (United States)

    Garino, Claudio; Gallo, Erik; Smolentsev, Nikolay; Glatzel, Pieter; Gobetto, Roberto; Lamberti, Carlo; Sadler, Peter J; Salassa, Luca

    2012-11-28

    Resonant X-ray Emission Spectroscopy (RXES) is used to characterize the ligand field states of the prototypic self-assembled square-planar complex, [Pt(tpy)Cl]Cl (tpy=2,2':6',2''-terpyridine), and determine the effect of weak metal-metal and π-π interactions on their energy.

  19. OH concentration in an atmospheric-pressure methane-air flame from molecular-beam mass spectrometry and laser-absorption spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Cattolica, R.J.; Yoon, S.; Knuth, E.L.

    1982-01-01

    In evaluating experimental techniques for studying premixed atmospheric-pressure methane-air flames, analysts demonstrated that the molecular-beam mass-spectrometry technique adequately measures OH concentration, given careful design of the sampling probe and appropriate consideration for possible mass interferences. Perturbation of the OH concentration profile using various sampling probes indicates the importance of minimizing the length of the sampling-orifice channel to reduce composition relaxation during sampling. The accuracy of the MBMS method was determined by comparing the results with those from a laser-absorption spectroscopy system.

  20. Determination of the electron energy distribution function of a low temperature plasma from optical emission spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Dodt, Dirk Hilar

    2009-01-05

    The experimental determination of the electron energy distribution of a low pressure glow discharge in neon from emission spectroscopic data has been demonstrated. The spectral data were obtained with a simple overview spectrometer and analyzed using a strict probabilistic, Bayesian data analysis. It is this Integrated Data Analysis (IDA) approach, which allows the significant extraction of non-thermal properties of the electron energy distribution function (EEDF). The results bear potential as a non-invasive alternative to probe measurements. This allows the investigation of spatially inhomogeneous plasmas (gradient length smaller than typical probe sheath dimensions) and plasmas with reactive constituents. The diagnostic of reactive plasmas is an important practical application, needed e.g. for the monitoring and control of process plasmas. Moreover, the experimental validation of probe theories for magnetized plasmas as a long-standing topic in plasma diagnostics could be addressed by the spectroscopic method. (orig.)

  1. Exoplanet atmosphere. Thermal structure of an exoplanet atmosphere from phase-resolved emission spectroscopy.

    Science.gov (United States)

    Stevenson, Kevin B; Désert, Jean-Michel; Line, Michael R; Bean, Jacob L; Fortney, Jonathan J; Showman, Adam P; Kataria, Tiffany; Kreidberg, Laura; McCullough, Peter R; Henry, Gregory W; Charbonneau, David; Burrows, Adam; Seager, Sara; Madhusudhan, Nikku; Williamson, Michael H; Homeier, Derek

    2014-11-14

    Exoplanets that orbit close to their host stars are much more highly irradiated than their solar system counterparts. Understanding the thermal structures and appearances of these planets requires investigating how their atmospheres respond to such extreme stellar forcing. We present spectroscopic thermal emission measurements as a function of orbital phase ("phase-curve observations") for the highly irradiated exoplanet WASP-43b spanning three full planet rotations using the Hubble Space Telescope. With these data, we construct a map of the planet's atmospheric thermal structure, from which we find large day-night temperature variations at all measured altitudes and a monotonically decreasing temperature with pressure at all longitudes. We also derive a Bond albedo of 0.18(-0.12)(+0.07) and an altitude dependence in the hot-spot offset relative to the substellar point.

  2. Thermal structure of an exoplanet atmosphere from phase-resolved emission spectroscopy

    CERN Document Server

    Stevenson, Kevin B; Line, Michael R; Bean, Jacob L; Fortney, Jonathan J; Showman, Adam P; Kataria, Tiffany; Kreidberg, Laura; McCullough, Peter R; Henry, Gregory W; Charbonneau, David; Burrows, Adam; Seager, Sara; Madhusudhan, Nikku; Williamson, Michael H; Homeier, Derek

    2014-01-01

    Exoplanets that orbit close to their host stars are much more highly irradiated than their Solar System counterparts. Understanding the thermal structures and appearances of these planets requires investigating how their atmospheres respond to such extreme stellar forcing. We present spectroscopic thermal emission measurements as a function of orbital phase ("phase-curve observations") for the highly-irradiated exoplanet WASP-43b spanning three full planet rotations using the Hubble Space Telescope. With these data, we construct a map of the planet's atmospheric thermal structure, from which we find large day-night temperature variations at all measured altitudes and a monotonically decreasing temperature with pressure at all longitudes. We also derive a Bond albedo of 0.18 +0.07,-0.12 and an altitude dependence in the hot-spot offset relative to the substellar point.

  3. Determination of ammonium and organic bound nitrogen by inductively coupled plasma emission spectroscopy.

    Science.gov (United States)

    Jaber, A M Y; Mehanna, N A; Sultan, S M

    2009-06-15

    The continuous flow sample introduction technique with a hydride generator system in conjunction with an inductively coupled plasma emission spectrometer (ICP-AES-HG), is used in this study for quantitative determination of ammonium and organic bound nitrogen in aqueous and solid samples. Ammonia vapor released from ammonium salt after treatment with concentrated NaOH is transferred by argon to plasma for detection at 174.273 nm using axial argon plasma mode. The calibration curves were linear within a range of 25-1000 mg L(-1)N as ammonium molybdate with correlation coefficients of better than 0.99 and limits of detection of about 10-25mg L(-1)N. The percent recovery of N (25-500 mg L(-1)N) in soft (distilled) water and high salt content (1.7 mol L(-1) NaCl) matrices was found to be in the range of about 97-102% with %RSD in the range of 4.6-0.62. The sensitivity, limit of detection, and blank contribution from the atmospheric nitrogen, were tremendously improved in this method compared with the available ICP-AES spray chamber counterpart. Furthermore, the ICP-AES-HG method gave results for real samples (soil, fertilizer, waste water) containing about 50-1800 mg L(-1)N in good agreement with those obtained by the standard Kjeldahl method. No statistical differences at the 95% confidence level on applying the t-test were observed between the values obtained by the two methods. Thus, the ICP-AES-HG method is reliable and faster than the conventional tedious Kjeldahl method, superior to the ICP-AES spray chamber method, and almost free from matrix interference which is usually a critical factor in atomic emission spectroscopic techniques.

  4. Single and double core-hole ion emission spectroscopy of transient neon plasmas produced by ultraintense x-ray laser pulses

    Science.gov (United States)

    Gao, Cheng; Zeng, Jiaolong; Yuan, Jianmin

    2016-05-01

    Single core-hole (SCH) and double core-hole (DCH) spectroscopy is investigated systematically for neon gas in the interaction with ultraintense x-ray pulses with photon energy from 937 eV to 2000 eV. A time-dependent rate equation, implemented in the detailed level accounting approximation, is utilized to study the dynamical evolution of the level population and emission properties of the laser-produced highly transient plasmas. The plasma density effects on level populations are demonstrated with an x-ray photon energy of 2000 eV. For laser photon energy in the range of 937 - 1360 eV, resonant absorptions (RA) of 1s-np (n> = 2) transitions play important roles in time evolution of the population and DCH emission spectroscopy. For x-ray photon energy larger than 1360 eV, no RA exist and transient plasmas show different features in the DCH spectroscopy.

  5. Measuring reactive nitrogen emissions from point sources using visible spectroscopy from aircraft.

    Science.gov (United States)

    Melamed, M L; Solomon, S; Daniel, J S; Langford, A O; Portmann, R W; Ryerson, T B; Nicks, D K; McKeen, S A

    2003-02-01

    Accurate measurements of nitrogen dioxide (NO2), a key trace gas in the formation and destruction of tropospheric ozone, are important in studies of urban pollution. Nitrogen dioxide column abundances were measured during the Texas Air Quality Study 2000 using visible absorption spectroscopy from an aircraft. The method allows for quantification of the integrated total number of nitrogen dioxide molecules in the polluted atmosphere and is hence a useful tool for measuring plumes of this key trace gas. Further, we show how such remote-sensing observations can be used to obtain information on the fluxes of nitrogen dioxide into the atmosphere with unique flexibility in terms of aircraft altitude, and the height and extent of mixing of the boundary layer. Observations of nitrogen dioxide plumes downwind of power plants were used to estimate the flux of nitrogen oxide emitted from several power plants in the Houston and Dallas metropolitan areas and in North Carolina. Measurements taken over the city of Houston were also employed to infer the total flux from the city as a whole.

  6. Source fingerprint monitoring of air pollutants from petrochemical industry and the determination of their annual emission flux using open path Fourier transform infrared spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Yih-Shiaw Huang; Shih-Yi Chang; Tai-Ly Tso [National Tsing Hua Univ., Hsinchu (China)

    1996-12-31

    Toxic air pollutants were investigated in several petrochemical industrial park in Taiwan using a movable open-path Fourier-transform infrared spectroscopy (FTIR). The results show the qualitative and quantitative analysis of emission gases from plants, and also provide the emission rates of various compounds. More than twenty compounds under usual operation were found from these industrial park. The concentration variation with time could be correlated exactly with the distances from the emission source along the wind direction. This means that by changing the measuring points the source of emission could be unambiguously identified. The point, area and line source (PAL) plume dispersion model has been applied to estimate the emission rate of either a point or an area source. The local atmospheric stability was determined by releasing an SF{sub 6} tracer. The origin of errors came mainly from the uncertainty of the source configuration and the variation of the meteorological condition. Through continuous measurement using a portable open-path Fourier transform infrared (POP-FTIR) spectrometer, the maximum value of the emission rate and the annual amount of emission could be derived. The emission rate of the measured toxic gases was derived by the model technique, and the results show that the emission amount is on the order of ten to hundred tons per year.

  7. Development of wavelength-dispersive soft X-ray emission spectrometers for transmission electron microscopes--an introduction of valence electron spectroscopy for transmission electron microscopy.

    Science.gov (United States)

    Terauchi, Masami; Koike, Masato; Fukushima, Kurio; Kimura, Atsushi

    2010-01-01

    Two types of wavelength-dispersive soft X-ray spectrometers, a high-dispersion type and a conventional one, for transmission electron microscopes were constructed. Those spectrometers were used to study the electronic states of valence electrons (bonding electrons). Both spectrometers extended the acceptable energy regions to higher than 2000 eV. The best energy resolution of 0.08 eV was obtained for an Al L-emission spectrum by using the high-dispersion type spectrometer. By using the spectrometer, C K-emission of carbon allotropes, Cu L-emission of Cu(1-x)Zn(x) alloys and Pt M-emission spectra were presented. The FWHM value of 12 eV was obtained for the Pt Malpha-emission peak. The performance of the conventional one was also presented for ZnS and a section specimen of a multilayer device. W-M and Si-K emissions were clearly resolved. Soft X-ray emission spectroscopy based on transmission electron microscopy (TEM) has an advantage for obtaining spectra from a single crystalline specimen with a defined crystal setting. As an example of anisotropic soft X-ray emission, C K-emission spectra of single crystalline graphite with different crystal settings were presented. From the spectra, density of states of pi- and sigma-bondings were separately derived. These results demonstrated a method to analyse the electronic states of valence electrons of materials in the nanometre scale based on TEM.

  8. Measuring PAH Emission in Ultradeep Spitzer IRS Spectroscopy of High Redshift IR Luminous Galaxies

    CERN Document Server

    Teplitz, H I; Armus, L; Chary, R; Marshall, J A; Colbert, J W; Frayer, D T; Pope, A; Blain, A; Spoon, H; Charmandaris, V; Scott, D

    2007-01-01

    The study of the dominant population of high redshift IR-luminous galaxies (10^11 - 10^12 Lsun at 1emission in all four targets, and compare the spectra to those of local galaxies observed by the IRS. The z=1.09 source appears to be a typical, star-formation dominated IR-luminous galaxy, while the z=2.69 source is a composite source with strong star formation and a prominent AGN. The IRAC colors of this source show no evidence of rest-frame near-infrared stellar photospheric...

  9. Optimal emission enhancement in orthogonal double-pulse laser-induced breakdown spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Sanginés, R. [Centro de Ciencias Aplicadas y Desarrollo Tecnológico, Universidad Nacional Autónoma de México (CCADET-UNAM), Apartado Postal 70-186, México, DF 04510 (Mexico); Cátedra CONACyT, Centro de Nanociencias y Nanotecnología, Universidad Nacional Autónoma de México, Apartado Postal 14, Ensenada, BC 22800 (Mexico); Contreras, V. [Department of Physics, Tampere University of Technology, P.O. Box 692, FI-33101 Tampere (Finland); Sobral, H., E-mail: martin.sobral@ccadet.unam.mx [Centro de Ciencias Aplicadas y Desarrollo Tecnológico, Universidad Nacional Autónoma de México (CCADET-UNAM), Apartado Postal 70-186, México, DF 04510 (Mexico); Robledo-Martinez, A. [Universidad Autónoma Metropolitana-Unidad Azcapotzalco, Av. San Pablo 180, Azcapotzalco, México, DF 02200 (Mexico)

    2015-08-01

    Orthogonal double-pulse (DP) laser-induced breakdown spectroscopy (LIBS) was performed using reheating and pre-ablative configurations. The ablation pulse power density was varied by two orders of magnitude and the DP experiments were carried out for a wide range of interpulse delays. For both DP-LIBS schemes, the signal enhancement was evaluated with respect to the corresponding single-pulse (SP) LIBS as a function of the interpulse delay. The reheating scheme shows a sharp maximum signal enhancement of up to 200-fold for low ablative power densities (0.4 GW cm{sup −2}); however, for power densities larger than 10 GW cm{sup −2} this configuration did not improve the SP outcome. On the other hand, a more uniform signal enhancement of about 4–6 was obtained for the pre-ablative scheme nearly independently of the used ablative power density. In terms of the signal-to-noise ratio (SNR) the pre-ablative scheme shows a monotonic increment with the ablative power density. Whereas the reheating configuration reaches a maximum at 2.2 GW cm{sup −2}, its enhancement effect collapses markedly for fluencies above 10 GW cm{sup −2}. - Highlights: • Comparison of reheating and pre-ablative double-pulse LIBS was done using a wide range of ablation power densities. • Experimental parameters that could achieve optimal signal-to-noise ratio were investigated. • A reheating scheme is better for low-ablation power densities. • A pre-ablative configuration is better for high-ablation power densities.

  10. Cost and CO2 emission optimization of precast prestressed concrete U-beam road bridges by a hybrid glowworm swarm algorithm

    OpenAIRE

    Yepes Piqueras, Víctor; Martí Albiñana, José Vicente

    2015-01-01

    This paper describes a methodology to optimize cost and CO2 emissions when designing precast-prestressed concrete road bridges with a double U-shape cross-section. To this end, a hybrid glowworm swarm optimization algorithm (SAGSO) is used to combine the synergy effect of the local search with simulated annealing (SA) and the global search with glowworm swarm optimization (GSO). The solution is defined by 40 variables, including the geometry, materials and reinforcement of the beam and the sl...

  11. X-ray Emission Spectroscopy to Study Ligand Valence Orbitals in Mn Coordination Complexes

    Energy Technology Data Exchange (ETDEWEB)

    Smolentsev, Grigory; Soldatov, Alexander V; Messinger, Johannes; Merz, Kathrin; Weyhermuller, Thomas; Bergmann, Uwe; Pushkar, Yulia; Yano, Junko; Yachandra, Vittal K.; Glatzel, Pieter

    2009-03-02

    We discuss a spectroscopic method to determine the character of chemical bonding and for the identification of metal ligands in coordination and bioinorganic chemistry. It is based on the analysis of satellite lines in X-ray emission spectra that arise from transitions between valence orbitals and the metal ion 1s level (valence-to-core XES). The spectra, in connection with calculations based on density functional theory (DFT), provide information that is complementary to other spectroscopic techniques, in particular X-ray absorption (XANES and EXAFS). The spectral shape is sensitive to protonation of ligands and allows ligands, which differ only slightly in atomic number (e.g., C, N, O...), to be distinguished. A theoretical discussion of the main spectral features is presented in terms of molecular orbitals for a series of Mn model systems: [Mn(H2O)6]2+, [Mn(H2O)5OH]+, [Mn(H2O)5NH2]+, and [Mn(H2O)5NH3]2+. An application of the method, with comparison between theory and experiment, is presented for the solvated Mn2+ ion in water and three Mn coordination complexes, namely [LMn(acac)N3]BPh4, [LMn(B2O3Ph2)(ClO4)], and [LMn(acac)N]BPh4, where L represents 1,4,7-trimethyl-1,4,7-triazacyclononane, acac stands for the 2,4-pentanedionate anion, and B2O3Ph2 represents the 1,3-diphenyl-1,3-dibora-2-oxapropane-1,3-diolato dianion.

  12. Dynamics of bolaamphiphilic fluorescent polyenes in lipid bilayers from polarization emission spectroscopy.

    Science.gov (United States)

    Acuña, A Ulises; Amat-Guerri, Francisco; Quesada, Ernesto; Vélez, Marisela

    2006-06-20

    The rotational motions of the biamphiphilic polyenes (bolapolyenes) dimethyl all-(E)-octacosa-10,12,14,16,18-pentaenedioate (DE28:5) and dimethyl all-(E)-tetratriaconta-13,15,17,19,21-pentaenedioate (DE34:5), with head-to-head distances of 34 and 42A, respectively, have been examined by fluorescence anisotropy methods. The membrane-spanning bolapolyenes, which contain a central emitting pentaene group tethered to two methoxycarbonyl opposite polar heads by symmetric C(8) (DE28:5) and C(11) (DE34:5) polymethylene chains, were dispersed in lipid bilayers of DPPC or DMPC, and the stationary and picosecond-resolved emission was recorded as a function of temperature. In fluid-phase DMPC bilayers, three relaxation times could be determined, assigned to fast (0.2 and 2ns) single-bond isomerization processes localized on the alkyl chains, and to whole-molecule oscillations ( approximately 11ns), respectively. The anisotropy decay parameters were further analyzed in terms of a diffusive model for wobbling in a Gaussian ordering potential, to assess the anchoring effect of the symmetric polar heads. In this way, the average rotational diffusion constant of the bolapolyenes, D( perpendicular), could be estimated as 0.022-0.026rad(2) ns(-1) (DMPC bilayers, 35 degrees Celsius), a value that is only 1/3 of that corresponding to the related pentaene fatty acid spanning a single membrane monolayer. In contrast, the amplitude of the equilibrium orientational distribution (theta(half-cone) approximately 50 degrees ) is very similar for both the transmembrane and the single-headed polyenes. The reorientational oscillations of the central emitting group in the bolapolyenes necessarily would produce large-amplitude (2-5A) and very fast (ns) translational motions of the polar heads.

  13. Energy level spectroscopy of InSb quantum wells using quantum-well LED emission

    Science.gov (United States)

    Tenev, T. G.; Palyi, A.; Mirza, B. I.; Nash, G. R.; Fearn, M.; Smith, S. J.; Buckle, L.; Emeny, M. T.; Ashley, T.; Jefferson, J. H.; Lambert, C. J.

    2009-02-01

    We have investigated the low-temperature optical properties of InSb quantum-well (QW) light-emitting diodes, with different barrier compositions, as a function of well width. Three devices were studied: QW1 had a 20 nm undoped InSb quantum well with a barrier composition of Al0.143In0.857Sb , QW2 had a 40 nm undoped InSb well with a barrier composition of Al0.077In0.923Sb , and QW3 had a 100 nm undoped InSb well with a barrier composition of Al0.025In0.975Sb . For QW1, the signature of two transitions (CB1-HH1 and CB1-HH2) can be seen in the measured spectrum, whereas for QW2 and QW3 the signature of a large number of transitions is present in the measured spectra. In particular transitions to HH2 can be seen, the first time this has been observed in AlInSb/InSb heterostructures. To identify the transitions that contribute to the measured spectra, the spectra have been simulated using an eight-band k.p calculation of the band structure together with a first-order time-dependent perturbation method (Fermi golden rule) calculation of spectral emittance, taking into account broadening. In general there is good agreement between the measured and simulated spectra. For QW2 we attribute the main peak in the experimental spectrum to the CB2-HH1 transition, which has the highest overall contribution to the emission spectrum of QW2 compared with all the other interband transitions. This transition normally falls into the category of “forbidden transitions,” and in order to understand this behavior we have investigated the momentum matrix elements, which determine the selection rules of the problem.

  14. FLASH SPECTROSCOPY: EMISSION LINES FROM THE IONIZED CIRCUMSTELLAR MATERIAL AROUND <10-DAY-OLD TYPE II SUPERNOVAE

    Energy Technology Data Exchange (ETDEWEB)

    Khazov, D.; Yaron, O.; Gal-Yam, A.; Manulis, I.; Rubin, A.; Ofek, E. O.; Horesh, A. [Benoziyo Center for Astrophysics, Faculty of Physics, The Weizmann Institute for Science, Rehovot 76100 (Israel); Kulkarni, S. R.; Kasliwal, M. M.; Cao, Y.; Perley, D. [Astronomy Department, California Institute of Technology, 1200 E. California Boulevard, Pasadena, CA 91125 (United States); Arcavi, I.; Howell, D. A. [Las Cumbres Observatory Global Telescope Network, 6740 Cortona Drive, Suite 102, Goleta, CA 93111 (United States); Sollerman, J. [The Oskar Klein Centre, Department of Astronomy, Stockholm University, AlbaNova, SE-10691 Stockholm (Sweden); Sullivan, M. [School of Physics and Astronomy, University of Southampton, Southampton, SO17 1BJ (United Kingdom); Filippenko, A. V.; Nugent, P. E. [Department of Astronomy, University of California, Berkeley, CA 94720-3411 (United States); Cenko, S. B. [Astrophysics Science Division, NASA Goddard Space Flight Center, Mail Code 661, Greenbelt, MD 20771 (United States); Silverman, J. M. [Department of Astronomy, University of Texas at Austin, Austin, TX 78712 (United States); Ebeling, H. [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States); and others

    2016-02-10

    Supernovae (SNe) embedded in dense circumstellar material (CSM) may show prominent emission lines in their early-time spectra (≤10 days after the explosion), owing to recombination of the CSM ionized by the shock-breakout flash. From such spectra (“flash spectroscopy”), we can measure various physical properties of the CSM, as well as the mass-loss rate of the progenitor during the year prior to its explosion. Searching through the Palomar Transient Factory (PTF and iPTF) SN spectroscopy databases from 2009 through 2014, we found 12 SNe II showing flash-ionized (FI) signatures in their first spectra. All are younger than 10 days. These events constitute 14% of all 84 SNe in our sample having a spectrum within 10 days from explosion, and 18% of SNe II observed at ages <5 days, thereby setting lower limits on the fraction of FI events. We classified as “blue/featureless” (BF) those events having a first spectrum that is similar to that of a blackbody, without any emission or absorption signatures. It is possible that some BF events had FI signatures at an earlier phase than observed, or that they lack dense CSM around the progenitor. Within 2 days after explosion, 8 out of 11 SNe in our sample are either BF events or show FI signatures. Interestingly, we found that 19 out of 21 SNe brighter than an absolute magnitude M{sub R} = −18.2 belong to the FI or BF groups, and that all FI events peaked above M{sub R} = −17.6 mag, significantly brighter than average SNe II.

  15. Femtosecond time-resolved X-ray absorption spectroscopy of liquid using a hard X-ray free electron laser in a dual-beam dispersive detection method.

    Science.gov (United States)

    Obara, Yuki; Katayama, Tetsuo; Ogi, Yoshihiro; Suzuki, Takayuki; Kurahashi, Naoya; Karashima, Shutaro; Chiba, Yuhei; Isokawa, Yusuke; Togashi, Tadashi; Inubushi, Yuichi; Yabashi, Makina; Suzuki, Toshinori; Misawa, Kazuhiko

    2014-01-13

    We present femtosecond time-resolved X-ray absorption spectroscopy of aqueous solution using a hard x-ray free electron laser (SACLA) and a synchronized Ti:sapphire laser. The instrumental response time is 200 fs, and the repetition rate of measurement is 10 Hz. A cylindrical liquid beam 100 μm in diameter of aqueous ammonium iron(III) oxalate solution is photoexcited at 400 nm, and the transient X-ray absorption spectra are measured in the K-edge region of iron, 7.10 - 7.26 keV, using a dual X-ray beam dispersive detection method. Each of the dual beams has the pulse energy of 1.4 μJ, and pump-induced absorbance change on the order of 10(-3) is successfully detected. The photoexcited iron complex exhibits a red shifted iron K-edge with the appearance time constant of 260 fs. The X-ray absorption difference spectra, with and without the pump pulses, are independent of time delay after 1.5 ps up to 100 ps, indicating that the photoexcited species is long-lived.

  16. Resonant soft X-ray emission spectroscopy of vanadium oxides andrelated compounds

    Energy Technology Data Exchange (ETDEWEB)

    Schmitt, Thorsten [Uppsala Univ. (Sweden)

    2004-01-01

    In today's information world, bits of data are processed by semiconductor chips, and stored in the magnetic disk drives. But tomorrow's information technology may see magnetism (spin) and semiconductivity (charge) combined in one ''spintronic'' device that exploits both charge and ''spin'' to carry data (the best of two worlds). Spintronic devices such as spin valve transistors, spin light emitting diodes, non-volatile memory, logic devices, optical isolators and ultra-fast optical switches are some of the areas of interest for introducing the ferromagnetic properties at room temperature in a semiconductor to make it multifunctional. The potential advantages of such spintronic devices will be higher speed, greater efficiency, and better stability at a reduced power consumption. This Thesis contains two main topics: In-depth understanding of magnetism in Mn doped ZnO, and our search and identification of at least six new above room temperature ferromagnetic semiconductors. Both complex doped ZnO based new materials, as well as a number of nonoxides like phosphides, and sulfides suitably doped with Mn or Cu are shown to give rise to ferromagnetism above room temperature. Some of the highlights of this work are discovery of room temperature ferromagnetism in: (1) ZnO:Mn (paper in Nature Materials, Oct issue, 2003); (2) ZnO doped with Cu (containing no magnetic elements in it); (3) GaP doped with Cu (again containing no magnetic elements in it); (4) Enhancement of Magnetization by Cu co-doping in ZnO:Mn; and (5) CdS doped with Mn, and a few others not reported in this thesis. We discuss in detail the first observation of ferromagnetism above room temperature in the form of powder, bulk pellets, in 2-3 μm thick transparent pulsed laser deposited films of the Mn (< 4 at.%) doped ZnO. High-resolution transmission electron microscopy (HRTEM) and electron energy loss spectroscopy (EELS) spectra recorded from 2 to 200nm

  17. Resonant soft X-ray emission spectroscopy of vanadium oxides andrelated compounds

    Energy Technology Data Exchange (ETDEWEB)

    Schmitt, Thorsten

    2004-11-01

    In today's information world, bits of data are processed by semiconductor chips, and stored in the magnetic disk drives. But tomorrow's information technology may see magnetism (spin) and semiconductivity (charge) combined in one ''spintronic'' device that exploits both charge and ''spin'' to carry data (the best of two worlds). Spintronic devices such as spin valve transistors, spin light emitting diodes, non-volatile memory, logic devices, optical isolators and ultra-fast optical switches are some of the areas of interest for introducing the ferromagnetic properties at room temperature in a semiconductor to make it multifunctional. The potential advantages of such spintronic devices will be higher speed, greater efficiency, and better stability at a reduced power consumption. This Thesis contains two main topics: In-depth understanding of magnetism in Mn doped ZnO, and our search and identification of at least six new above room temperature ferromagnetic semiconductors. Both complex doped ZnO based new materials, as well as a number of nonoxides like phosphides, and sulfides suitably doped with Mn or Cu are shown to give rise to ferromagnetism above room temperature. Some of the highlights of this work are discovery of room temperature ferromagnetism in: (1) ZnO:Mn (paper in Nature Materials, Oct issue, 2003); (2) ZnO doped with Cu (containing no magnetic elements in it); (3) GaP doped with Cu (again containing no magnetic elements in it); (4) Enhancement of Magnetization by Cu co-doping in ZnO:Mn; and (5) CdS doped with Mn, and a few others not reported in this thesis. We discuss in detail the first observation of ferromagnetism above room temperature in the form of powder, bulk pellets, in 2-3 {micro}m thick transparent pulsed laser deposited films of the Mn (< 4 at.%) doped ZnO. High-resolution transmission electron microscopy (HRTEM) and electron energy loss spectroscopy (EELS) spectra recorded from 2 to 200nm

  18. Fingerprinting of complex mixtures with the use of high performance liquid chromatography, inductively coupled plasma atomic emission spectroscopy and chemometrics

    Energy Technology Data Exchange (ETDEWEB)

    Ni Yongnian [Department of Chemistry, Nanchang University, Nanchang, Jiangxi 330047 (China)], E-mail: ynni@ncu.edu.cn; Peng Yunyan [Department of Chemistry, Nanchang University, Nanchang, Jiangxi 330047 (China); Kokot, Serge [Inorganic Materials Program, School of Physical and Chemical Sciences, Queensland University of Technology, Brisbane, Queensland 4001 (Australia)

    2008-05-26

    The molecular and metal profile fingerprints were obtained from a complex substance, Atractylis chinensis DC-a traditional Chinese medicine (TCM), with the use of the high performance liquid chromatography (HPLC) and inductively coupled plasma atomic emission spectroscopy (ICP-AES) techniques. This substance was used in this work as an example of a complex biological material, which has found application as a TCM. Such TCM samples are traditionally processed by the Bran, Cut, Fried and Swill methods, and were collected from five provinces in China. The data matrices obtained from the two types of analysis produced two principal component biplots, which showed that the HPLC fingerprint data were discriminated on the basis of the methods for processing the raw TCM, while the metal analysis grouped according to the geographical origin. When the two data matrices were combined into a one two-way matrix, the resulting biplot showed a clear separation on the basis of the HPLC fingerprints. Importantly, within each different grouping the objects separated according to their geographical origin, and they ranked approximately in the same order in each group. This result suggested that by using such an approach, it is possible to derive improved characterisation of the complex TCM materials on the basis of the two kinds of analytical data. In addition, two supervised pattern recognition methods, K-nearest neighbors (KNNs) method, and linear discriminant analysis (LDA), were successfully applied to the individual data matrices-thus, supporting the PCA approach.

  19. Spectroscopy of superluminous supernova host galaxies. A preference of hydrogen-poor events for extreme emission line galaxies

    CERN Document Server

    Leloudas, G; Kruehler, T; Gorosabel, J; Christensen, L; Mehner, A; Postigo, A de Ugarte; Amorin, R; Thoene, C C; Anderson, J P; Bauer, F E; Gallazzi, A; Helminiak, K G; Hjorth, J; Ibar, E; Malesani, D; Morell, N; Vinko, J; Wheeler, J C

    2014-01-01

    Superluminous supernovae (SLSNe) were only discovered recently due to their preference for occurring in faint dwarf galaxies. Understanding why stellar evolution yields different types of stellar explosions in these environments is fundamental in order to both uncover the elusive progenitors of SLSNe and to study star formation in dwarf galaxies. In this paper, we present the first results of our project to study SUperluminous Supernova Host galaxIES (SUSHIES), focusing on the sample for which we have obtained spectroscopy. We show that SLSNe-I and SLSNe-R (hydrogen-poor) often (~50% in our sample) occur in a class of galaxies that is known as Extreme Emission Line Galaxies (EELGs). The probability of this happening by chance is negligible and we therefore conclude that the extreme environmental conditions and the SLSN phenomenon are related. In contrast, SLSNe-II (hydrogen-rich) occur in more massive, more metal-rich galaxies with softer radiation fields. Therefore, if SLSNe-II constitute a uniform class, th...

  20. Elemental Content in Brown Rice by Inductively Coupled Plasma Atomic Emission Spectroscopy Reveals the Evolution of Asian Cultivated Rice

    Institute of Scientific and Technical Information of China (English)

    Yawen Zeng; Luxiang Wang; Juan Du; Jiafu Liu; Shuming Yang; Xiaoying Pu; Fenghui Xiao

    2009-01-01

    The phylogenetic relationship for classification traits and eight mineral elements in brown rice (Oryza sativa L.) from Yunnan Province in China was carried out using microwave assisted digestion followed by inductively coupled plasma atomic emission spectroscopy, and the analytical procedures were carefully controlled and validated. In general, the results show that the mean levels of K, Ca, Mg, Fe and Cu in brown rice for 789 accessions of rice landraces was distinctly lower than that of improved cultivars. They further demonstrate that Ca plays an important role in the differentiation of subspecies indica-japonica, especially to enhance adaptation of cold stress, and that five mineral elements in brown rice enhance the eurytopicity from landrace to improved cultivar. Hierarchical cluster analysis, using average linkage from SPSS software based on eight mineral elements in brown rice, showed that Yunnan rice could be grouped into rice landrace and improved cultivar, with the rice landrace being further clustered into five subgroups, and that, interestingly, purple rice does not cluster with either of the groups. Our present data confirm that indica is the closest relative of late rice and white rice, and that they constitute rice landraces together, whereas japonica is the closest relatives of non-nuda, early-mid and glutinous rice. It is further shown that japonica, non-nuda, early-mid, glutinous, white and red rice might be more primitive than indica, nuda, late, non-glutinous and purple rice, respectively.

  1. Research as a guide for curriculum development: An example from introductory spectroscopy. II. Addressing student difficulties with atomic emission spectra

    Science.gov (United States)

    Ivanjek, L.; Shaffer, P. S.; McDermott, L. C.; Planinic, M.; Veza, D.

    2015-02-01

    This is the second of two closely related articles (Paper I and Paper II) that together illustrate how research in physics education has helped guide the design of instruction that has proved effective in improving student understanding of atomic spectroscopy. Most of the more than 1000 students who participated in this four-year investigation were science majors enrolled in the introductory calculus-based physics course at the University of Washington (UW) in Seattle, WA, USA. The others included graduate and undergraduate teaching assistants at UW and physics majors in introductory and advanced physics courses at the University of Zagreb, Zagreb, Croatia. About half of the latter group were preservice high school physics teachers. Paper I describes how several conceptual and reasoning difficulties were identified among university students as they tried to relate a discrete line spectrum to the energy levels of atoms in a light source. This second article (Paper II) illustrates how findings from this research informed the development of a tutorial that led to improvement in student understanding of atomic emission spectra.

  2. Magnetic Resonance Spectroscopy and Single-Photon Emission Computed Tomography in the Evaluation of Cerebral Tumors: A Case Report

    Science.gov (United States)

    Siasios, Ioannis; Valotassiou, Varvara; Kapsalaki, Eftychia; Tsougos, Ioannis; Georgoulias, Panagiotis; Fotiadou, Aggeliki; Ioannou, Maria; Koukoulis, Georgios; Dimopoulos, Vassilios; Fountas, Kostas

    2017-01-01

    In their daily clinical practice, physicians have to confront diagnostic dilemmas which cannot be resolved by the application of only one imaging technique. In this case report, we present a 66-year-old woman who was admitted to our institution for the surgical resection of a recently diagnosed brain tumor. The patient had a history of epileptic seizures and was hospitalized in the past for anti-phospholipid syndrome related to a non-Hodgkin lymphoma in remission. Magnetic resonance imaging (MRI) examination revealed an enhancing right parasagittal lesion with significant edema suggestive of a high grade glioma. Advanced MRI techniques including proton magnetic resonance spectroscopy (1H-MRS) showed findings compatible of glioma. An additional examination was performed as part of a protocol that we are routinely performing in our institution for all brain tumors including not only the gold standard advanced MRI techniques but also single-photon emission computed tomography (SPECT) with technetium-99m (Tc99m). Brain SPECT indicated the presence of a meningioma which was verified by the histopathology of the resected specimen. In conclusion, a multimodality approach for the pre-surgical assessment of brain tumors has significant advantages not only for the diagnosis but also for the evaluation of intracranial tumors histology. PMID:27924180

  3. Optical emission spectroscopy of OH lines in N2 and Ar plasma during the treatments of cotton fabric

    Science.gov (United States)

    Skoro, Nikola; Puac, Nevena; Spasic, Kosta; Malovic, Gordana; Gorjanc, Marija; Petrovic, Zoran Lj

    2016-09-01

    Low pressure non-equilibrium plasmas are proven to be irreplaceable tool in material processing. Among other fields their applications in treatments of textiles are still diversifying, but the main role of plasma is activation of the surface of treated sample. After, or during, the treatments these surfaces can be covered with different materials or species (such as microcapsules) that enhance properties of the fabric. In order to investigate mechanisms how active species from plasma interact with the cotton surface, we studied both plasma and surface properties. Bleached cotton samples were treated in low-pressure nitrogen and argon plasma in a chamber with parallel-plate electrodes. The effect of the plasma treatment on the cotton samples was investigated with the colorimetric measurements on dyes absorption by a spectrophotometer. Optical emission spectroscopy was performed by using spectrometer with a sensitive CCD camera. We have recorded the evolution of the maximum of the intensity of OH and N2 second positive band lines. Measurement were done with and without samples in the chamber and comparison between the lines intensity was made. The parameters for optimal plasma treatment conditions were determined. Research supported by the MESTD, projects III41011 and ON171037.

  4. Determination of plasma trace elements in tumor-bearing animals by proton-induced X-ray emission spectroscopy.

    Science.gov (United States)

    Fogle, M; Daly, B; Evans, M; Justiniano, E L; Kovacs, C J; Shinpaugh, J L; Toburen, L H

    2001-11-01

    Although altered levels of circulating essential trace elements are known to accompany malignant disease, the lack of sensitivity of conventional detection methods has generally limited their study to clinical conditions involving extensive disease (i.e., significant tumor burden). As such, the application of altered trace element levels as potential prognostic guides or as response indicators subsequent to treatment has been of limited use. During this study, proton-induced X-ray emission spectroscopy was evaluated as a tool to determine trace element imbalances in a murine tumor model. Using plasma from C57B1/6 mice bearing the syngeneic Lewis lung carcinoma (LLCa), levels of Fe, Cu, and Zn, as well as changes in the Cu /Zn ratio, were measured in animals carrying an increasing primary tumor burden. The plasma levels of Fe, Cu, and Zn were found to decrease significantly 7 d following implants of LLCa cells with no significant change observed in the Cu/Zn ratio. By d 21, however, an increase in the Cu/Zn ratio was found to accompany increased growth of the LLCa tumor; the plasma levels of Cu had returned to normal levels, whereas both the Fe and Zn plasma levels remained lowered. Collectively, the results suggest that although a net change in individual plasma trace element concentrations might not be accurately associated with tumor growth, a clear relationship was established between the Cu/Zn ratio and tumor size.

  5. 57Fe emission Mössbauer spectroscopy following dilute implantation of 57Mn into In 2O3

    Science.gov (United States)

    Mokhles Gerami, A.; Johnston, K.; Gunnlaugsson, H. P.; Nomura, K.; Mantovan, R.; Masenda, H.; Matveyev, Y. A.; Mølholt, T. E.; Ncube, M.; Shayestehaminzadeh, S.; Unzueta, I.; Gislason, H. P.; Krastev, P. B.; Langouche, G.; Naidoo, D.; Ólafsson, S.

    2016-12-01

    Emission Mössbauer spectroscopy has been utilised to characterize dilute 57Fe impurities in In 2O3 following implantation of 57Mn ( T 1/2 = 1.5 min.) at the ISOLDE facility at CERN. From stoichiometry considerations, one would expect Fe to adopt the valence state 3 + , substituting In 3+, however the spectra are dominated by spectral lines due to paramagnetic Fe2+. Using first principle calculations in the framework of density functional theory (DFT), the density of states of dilute Fe and the hyperfine parameters have been determined. The hybridization between the 3d-band of Fe and the 2p band of oxygen induces a spin-polarized hole on the O site close to the Fe site, which is found to be the cause of the Fe2+ state in In 2O3. Comparison of experimental data to calculated hyperfine parameters suggests that Fe predominantly enters the 8b site rather than the 24d site of the cation site in the Bixbyite structure of In 2O3. A gradual transition from an amorphous to a crystalline state is observed with increasing implantation/annealing temperature.

  6. Optical emission spectroscopy of deuterium and helium plasma jets emitted from plasma focus discharges at the PF-1000U facility

    Science.gov (United States)

    Skladnik-Sadowska, E.; Dan'ko, S. A.; Kwiatkowski, R.; Sadowski, M. J.; Zaloga, D. R.; Paduch, M.; Zielinska, E.; Kharrasov, A. M.; Krauz, V. I.

    2016-12-01

    Optical emission spectroscopy techniques were used to investigate the spectra of dense deuterium-plasma jets generated by high-current pulse discharges within the large PF-1000U facility and to estimate parameters of plasma inside the jets and their surroundings. Time-resolved optical spectra were recorded by means of a Mechelle®900 spectrometer. From an analysis of the deuterium line broadening, it was estimated that the electron concentration at a distance 57 cm from the electrode outlets amounted to (0.4-3.7) × 1017 cm-3 depending on the initial gas distribution and the time interval of the spectrum registration after the instant of the plasma jet generation. From the re-absorption dip in the Dβ profile, it was assessed that the electron concentration in the surrounding gas was equal to about 1.5 × 1015 cm-3. On the basis of the measured ratio of He II 468.6 nm and He I 587.6 nm line intensities, it was estimated that the electron temperature amounted to about 5.3 eV. Also estimated were some dimensionless parameters of the investigated plasma jets.

  7. Standard test method for determining elements in waste Streams by inductively coupled plasma-atomic emission spectroscopy

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2010-01-01

    1.1 This test method covers the determination of trace, minor, and major elements in waste streams by inductively coupled plasma-atomic emission spectroscopy (ICP-AES) following an acid digestion of the sample. Waste streams from manufacturing processes of nuclear and non-nuclear materials can be analyzed. This test method is applicable to the determination of total metals. Results from this test method can be used to characterize waste received by treatment facilities and to formulate appropriate treatment recipes. The results are also usable in process control within waste treatment facilities. 1.2 This test method is applicable only to waste streams that contain radioactivity levels that do not require special personnel or environmental protection. 1.3 A list of the elements determined in waste streams and the corresponding lower reporting limit is found in Table 1. 1.4 This test method has been used successfully for treatment of a large variety of waste solutions and industrial process liquids. The com...

  8. Insufficiency of Positron Emission Tomography and Magnetic Resonance Spectroscopy in the Diagnosis of Intravascular Lymphoma of the Central Nervous System

    Directory of Open Access Journals (Sweden)

    Nobuyuki Kawai

    2012-07-01

    Full Text Available Intravascular large B-cell lymphoma (IVL is a rare type of extranodal lymphoma with an aggressive clinical course characterized by the proliferation of lymphoma cells within the lumen of small vessels. Diagnosis is often difficult because of marked variability in clinical presentation and nonspecific laboratory and radiological findings, especially when central nervous system (CNS symptoms are the only manifestation. Modern metabolic imaging techniques such as positron emission tomography (PET and 1H-magnetic resonance spectroscopy (MRS have been reported to be useful in the diagnosis of conventional primary CNS lymphoma. We report the case of a 69-year-old man who presented with a progressive leukoencephalopathic syndrome. The patient was examined by 18F-fluorodeoxyglucose and 11C-methionine PET and MRS, but none of these examinations were able to show the presence of a tumor in the lesions or to clarify the tumor characteristics. Brain biopsy was the only way to obtain a definite diagnosis of IVL. The patient was treated intensively with standard immunochemotherapy but died 6 months after the diagnosis. Here, we discuss the insufficiency of modern metabolic imaging techniques, including PET and MRS, and recommend a rapid decision of brain biopsy in the diagnosis of IVL only involving the CNS.

  9. Research as a guide for curriculum development: An example from introductory spectroscopy. I. Identifying student difficulties with atomic emission spectra

    Science.gov (United States)

    Ivanjek, L.; Shaffer, P. S.; McDermott, L. C.; Planinic, M.; Veza, D.

    2015-01-01

    This is the first of two closely related articles (Paper I and Paper II) that together illustrate how research in physics education has helped guide the design of instruction that has proved effective in improving student understanding of atomic spectroscopy. Most of the more than 1000 students who participated in this four-year investigation were science majors enrolled in the introductory calculus-based physics course at the University of Washington (UW) in Seattle, WA, USA. The others included graduate and undergraduate teaching assistants at UW and physics majors in introductory and advanced physics courses at the University of Zagreb, Zagreb, Croatia. About half of the latter group were preservice high school physics teachers. This article (Paper I) describes how several serious conceptual and reasoning difficulties were identified among students as they tried to relate a discrete line spectrum to the energy levels of atoms in a light source. Paper II illustrates how findings from this research informed the development of a tutorial that led to significant improvement in student understanding of atomic emission spectra.

  10. Diagnosis of Methane Plasma Generated in an Atmospheric Pressure DBD Micro-Jet by Optical Emission Spectroscopy

    Institute of Scientific and Technical Information of China (English)

    ZHANG Jun-Feng; BIAN Xin-Chao; CHEN Qiang; LIU Fu-Ping; LIU Zhong-Wei

    2009-01-01

    Diagnosis of methane plasma,generated in an atmospheric pressure dielectric barrier discharge (DBD) microplasma jet with a quartz tube as dielectric material by a 25 kHz sinusoidal ac power source,is conducted by optical emission spectroscopy (OES).The reactive radicals in methane plasma such as CH,C2,and Ha are detected insitu by OES.The possible dissociation mechanism of methane in diluted Ar plasma is deduced from spectra.In addition,the density of CH radical,which is considered as one of the precursors in diamond-like (DLC) film formation,affected by the parameters of input voltage and the feed gas flow rate,is emphasized. With the Boltzmann plots,four Ar atomic spectral lines (located at 675.28nm,687.13nm,738.40nm and 794.82nm,respectively) are chosen to calculate the electron temperature,and the dependence of electron temperature on discharge parameters is also investigated.

  11. Measurements of Hard X-Ray Emission Suggest Absorption Along the Path of the Inner Beams in High Foot Implosion Experiments on the NIF

    Science.gov (United States)

    Ralph, Joseph; Pak, Arthur; Otto, Landen; Kritcher, Andrea; Ma, Tammy; Charles, Jarrott; Callahan, Debra; Hinkel, Denise; Berzak Hopkins, Laura; Moody, John; Khan, Shahab; Doeppner, Tilo; Rygg, Ryan; Hurricane, Omar

    2016-10-01

    The current high foot hohlraum design fielded on the National Ignition Facility is aimed at providing uniform x-ray drive to provide a spherical implosion by lowering the gas fill from 1.6 to 0.6 mg/cc and increasing the hohlraum width from 5.75 to 6.72 mm while maintaining the same 1.8 mm capsule diameter from previous designs. These changes are intended to improve beam propagation without the need for crossed beam energy transfer. Analysis of the measurements of hard x-ray emission from the gated x-ray detector (GXD) and the static x-ray imager (SXI) looking through the laser entrance hole indicate a significant fraction of the inner beam incident energy is absorbed in the high z blow-off region (either uranium or gold) before reaching the inner wall near the equator. Comparison of inner beam absorption in this region and its effect on the implosion symmetry measurements will be presented. Additionally, the sensitivity of this absorption feature and therefore the implosion symmetry to the pulse shape, hohlraum fill pressure and fraction of energy in beams depositing energy at the hohlraum equator will be discussed. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  12. Physical properties of emission-line galaxies at z ∼ 2 from near-infrared spectroscopy with Magellan fire

    Energy Technology Data Exchange (ETDEWEB)

    Masters, Daniel; Siana, Brian; Mobasher, Bahram; Domínguez, Alberto [Department of Physics and Astronomy, University of California, Riverside, CA 92521 (United States); McCarthy, Patrick; Blanc, Guillermo; Dressler, Alan [Carnegie Observatories, Pasadena, CA 91101 (United States); Malkan, Mathew; Ross, Nathaniel R. [Department of Physics and Astronomy, UCLA, Los Angeles, CA 90095 (United States); Atek, Hakim [Laboratoire d' Astrophysique Ecole Polytechnique Fédérale, CH-1290 Sauverny (Switzerland); Henry, Alaina [Astrophysics Science Division, Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Martin, Crystal L. [Department of Physics, Universitey of California, Santa Barbara, CA 93106 (United States); Rafelski, Marc; Colbert, James [Spitzer Science Center, California Institute of Technology, Pasadena, CA 91125 (United States); Hathi, Nimish P. [Aix Marseille Université, CNRS, LAM (Laboratoire d' Astrophysique de Marseille) UMR 7326, F-13388 Marseille (France); Scarlata, Claudia [Minnesota Institute for Astrophysics, University of Minnesota, Minneapolis, MN 55455 (United States); Bunker, Andrew J. [Department of Physics, University of Oxford (United Kingdom); Bedregal, Alejandro G. [Department of Physics and Astronomy, Tufts University, Medford, MA 02155 (United States); Teplitz, Harry [Infrared Processing and Analysis Center, Caltech, Pasadena, CA 91125 (United States)

    2014-04-20

    We present results from near-infrared spectroscopy of 26 emission-line galaxies at z ∼ 2.2 and z ∼ 1.5 obtained with the Folded-port InfraRed Echellette (FIRE) spectrometer on the 6.5 m Magellan Baade telescope. The sample was selected from the WFC3 Infrared Spectroscopic Parallels survey, which uses the near-infrared grism of the Hubble Space Telescope Wide Field Camera 3 (WFC3) to detect emission-line galaxies over 0.3 ≲ z ≲ 2.3. Our FIRE follow-up spectroscopy (R ∼ 5000) over 1.0-2.5 μm permits detailed measurements of the physical properties of the z ∼ 2 emission-line galaxies. Dust-corrected star formation rates for the sample range from ∼5-100 M {sub ☉} yr{sup –1} with a mean of 29 M {sub ☉} yr{sup –1}. We derive a median metallicity for the sample of 12 + log(O/H) = 8.34 or ∼0.45 Z {sub ☉}. The estimated stellar masses range from ∼10{sup 8.5}-10{sup 9.5} M {sub ☉}, and a clear positive correlation between metallicity and stellar mass is observed. The average ionization parameter measured for the sample, log U ≈ –2.5, is significantly higher than what is found for most star-forming galaxies in the local universe, but similar to the values found for other star-forming galaxies at high redshift. We derive composite spectra from the FIRE sample, from which we measure typical nebular electron densities of ∼100-400 cm{sup –3}. Based on the location of the galaxies and composite spectra on diagnostic diagrams, we do not find evidence for significant active galactic nucleus activity in the sample. Most of the galaxies, as well as the composites, are offset diagram toward higher [O III]/Hβ at a given [N II]/Hα, in agreement with other observations of z ≳ 1 star-forming galaxies, but composite spectra derived from the sample do not show an appreciable offset from the local star-forming sequence on the [O III]/Hβ versus [S II]/Hα diagram. We infer a high nitrogen-to-oxygen abundance ratio from the composite spectrum, which

  13. Measurements of urea and glucose in aqueous solutions with dual-beam near-infrared Fourier-transform spectroscopy

    DEFF Research Database (Denmark)

    Jensen, P.S.; Bak, J.

    2002-01-01

    of these two modes of operation. The concentrations of aqueous solutions of urea and glucose in the ranges 0-40 mg/dL and 0-250 mg/dL, respectively, were determined by principal component regression using both modes. The dual-beam technique eliminated instrumental variations present in the single...

  14. THE SMARTS MULTI-EPOCH OPTICAL SPECTROSCOPY ATLAS (SaMOSA): AN ANALYSIS OF EMISSION LINE VARIABILITY IN SOUTHERN HEMISPHERE FERMI BLAZARS

    Energy Technology Data Exchange (ETDEWEB)

    Isler, Jedidah C. [Chancellor’s Faculty Fellow, Syracuse University, Department of Physics, Syracuse, NY 13244 (United States); Urry, C. M.; Bailyn, C.; Coppi, P.; Brady, M.; MacPherson, E.; Hasan, I.; Buxton, M. [Department of Astronomy, Yale University, P.O. Box 208101, New Haven, CT 06520-8101 (United States); Smith, P. S., E-mail: jcisler@syr.edu [Steward Observatory, University of Arizona, 933 N. Cherry Avenue, Tuscon, AZ 85721 (United States)

    2015-05-01

    We present multi-epoch optical spectroscopy of seven southern Fermi-monitored blazars from 2008 to 2013 using the Small and Medium Aperture Research Telescope System (SMARTS), with supplemental spectroscopy and polarization data from the Steward Observatory. We find that the emission lines are much less variable than the continuum; four of seven blazars had no detectable emission line variability over the 5 yr observation period. This is consistent with photoionization primarily by an accretion disk, allowing us to use the lines as a probe of disk activity. Comparing optical emission line flux with Fermi γ-ray flux and optical polarized flux, we investigate whether relativistic jet variability is related to the accretion flow. In general, we see no such dependence, suggesting that the jet variability is likely caused by internal processes like turbulence or shock acceleration rather than a variable accretion rate. However, three sources showed statistically significant emission line flares in close temporal proximity to very large Fermi γ-ray flares. While we do not have sufficient emission line data to quantitatively assess their correlation with the γ-ray flux, it appears that in some cases the jet might provide additional photoionizing flux to the broad-line region (BLR), which implies that some γ-rays are produced within the BLR, at least for these large flares.

  15. Charge deep-level transient spectroscopy study of high-energy-electron-beam-irradiated hydrogenated amorphous silicon

    NARCIS (Netherlands)

    Klaver, A.; Nádaždy, V.; Zeman, M.; Swaaiij, R.A.C.M.M.

    2006-01-01

    We present a study of changes in the defect density of states in hydrogenated amorphous silicon (a-Si:H) due to high-energy electron irradiation using charged deep-level transient spectroscopy. It was found that defect states near the conduction band were removed, while in other band gap regions the

  16. GRB hosts through cosmic time. VLT/X-Shooter emission-line spectroscopy of 96 γ-ray-burst-selected galaxies at 0.1

    NARCIS (Netherlands)

    T. Krühler; D. Malesani; J.P.U. Fynbo; O.E. Hartoog; J. Hjorth; P. Jakobsson; D.A. Perley; A.. Rossi; P. Schady; S. Schulze; N.R. Tanvir; S.D. Vergani; K. Wiersema; P.M.J. Afonso; J. Bolmer; Z. Cano; S. Covino; V. D’Elia; A. de Ugarte Postigo; R. Filgas; M. Friis; J.F. Graham; J. Greiner; P. Goldoni; A. Gomboc; F. Hammer; J. Japelj; D.A. Kann; L. Kaper; S. Klose; A.J. Levan; G. Leloudas; B. Milvang-Jensen; A. Nicuesa Guelbenzu; E. Palazzi; E. Pian; S. Piranomonte; R. Sánchez-Ramírez; S. Savaglio; J. Selsing; G. Tagliaferri; P.M. Vreeswijk; D.J. Watson; D. Xu

    2015-01-01

    We present data and initial results from VLT/X-Shooter emission-line spectroscopy of 96 galaxies selected by long γ-ray bursts (GRBs) at 0.1

  17. VERITAS (Venus Emissivity, Radio Science, InSAR, Topo-graphy And Spectroscopy): A Proposed Discovery Mission

    Science.gov (United States)

    Smrekar, Suzanne; Dyar, Melinda; Hensley, Scott; Helbert, Joern; VERITAS Science Team

    2016-10-01

    VERITAS addresses one of the most fundamental questions in planetary evolution: How Earth-like is Venus? These twin planets diverged down different evolutionary paths, yet Venus may hold lessons for past and future Earth, as well as for Earth-sized exoplanets. VERITAS will search for the mineralogical fingerprints of past water, follow up on the discoveries of recent volcanism and the possible young surface age, and reveal the conditions that have prevented plate tectonics from developing. Collectively these questions address how Venus ended up a sulfurous inferno while Earth became habitable.VERITAS carries the Venus Interferometric Synthetic Aperture Radar (VISAR) and the Venus Emissivity Mapper (VEM), plus a gravity science investigation.The VISAR X-band radar produces: 1) a global digital elevation model (DEM) with 250 m postings, 5 m height accuracy, 2) Synthetic aperture radar (SAR) global imaging with 30 m pixels, 3) SAR imaging at 15 m for targeted areas, and 4) surface deformation from repeat pass interferometry (RPI) at 2 mm height precision for targeted, potentially active areas. VEM [see Helbert abstract] will measure surface emissivity, look for active volcanic flows and outgassing of water over ~78% of the surface using 6 NIR surface bands within 5 atmospheric windows and 8 bands for calibration of clouds, stray light, and water vapor.VERITAS uses Ka-band uplink and downlink to create a global gravity field with 3 mgal accuracy and 145 km resolution (130 spherical harmonic degree and order or d&o) and providing a significantly higher resolution field with much more uniform resolution than that available from Magellan.VERITAS will create a rich data set of high resolution topography, imaging, spectroscopy, and gravity. These co-registered data sets will be on par with those acquired for Mercury, Mars and the Moon that have revolutionized our understanding of these bodies. VERITAS would be a valuable asset for future lander or probe missions, collecting

  18. Multi-Beam Optical Tweezers

    OpenAIRE

    Glückstad, Jesper; Eriksen, Rene Lynge; Hanson, Steen Grüner

    2003-01-01

    A set of multi-beam electromagnetic tweezers is provided comprising a multi-beam generator for emission of a plurality of electromagnetic beams, at least some of the electromagnetic beams intersecting each other, or, having an individually controlled polarization whereby the position and/or angular orientation of a plurality of micro-objects may be individually controlled.A set of multi-beam electromagnetic tweezers is provided comprising a multi-beam generator for emission of a plurality of ...

  19. Characterisation of the properties of a negative hydrogen ion beam by several beam diagnostic techniques

    Science.gov (United States)

    Maurizio, R.; Fantz, U.; Bonomo, F.; Serianni, G.

    2016-06-01

    The beam properties of the BATMAN negative ion source, which is the prototype of one module of the source for the ITER neutral beam injection system, are characterised by means of three diagnostic techniques: beam emission spectroscopy (BES), the experimental calorimeter mini-STRIKE and a copper calorimeter. The main beam parameters—beam divergence, homogeneity and top-bottom asymmetries—are studied in different operational scenarios: with different magnetic filter field setups, source settings and with different gases (hydrogen or deuterium). Among all dependences, the influence of the magnetic field configuration on the beam and the evolution of the beam features during some conditioning days are investigated in detail. Data show that the stronger the filter field in the beam region, the higher the beam top-bottom asymmetry—likely a v× B effect. During the conditioning of the source, such vertical beam asymmetry increases as well, suggesting an inhomogeneous H -production at the first grid of the extraction system.

  20. Evaluation of lithium determination in three analyzers: flame emission, flame atomic absorption spectroscopy and ion selective electrode

    Directory of Open Access Journals (Sweden)

    Mehri Aliasgharpour

    2009-10-01

    Full Text Available Background: Lithium carbonate salt has become an increasingly important substance in the treatment of manic depressive disorders, and its relatively narrow therapeutic range has caused laboratories to monitor the serum concentration carefully. In the present work we evaluated lithium measurement in 3 different analyzers. Methods & Materials: Three different analyzers including Flame Emission (FES, Flame Atomic Absorption Spectroscopy (FAAS, and Ion Selective Electrode (ISE were used. All chemicals had a grade suitable for trace metal analysis. Results: Within-day precision of CV was ≤ 1.5% for FES & FAAS, except for ISE (1.9% CV. Between-days precision of CV was less for FES than for FAAS and ISE (1.3% versus 2.2% & 2.3%. The percent recovery of added lithium in pooled patients’ serum was higher for ISE than for FASS and FES (103.4% versus 96.2% and 94.6%. We also obtained a higher average lithium concentration for patients’ serum samples (n=16 measured by ISE than for FAAS and FES (0.825±0.30 versus 0.704±0.26 & 0.735±0.19. Paired t-test results revealed a significant difference (p< 0.001 for patient sera analyzed with FAAS and ISE. Conclusion: We report higher results for ISE than the other two analyzers and conclude that the choice between the two flame methods for patients’ serum lithium determination is arbitrary and that FES analyzer is a more attractive routine alternative for lithium determination than FAAS because of its cost and ease of performance. In addition, the results obtained by ISE are precise. However, its accuracy may depend on other interfering factors.

  1. In-beam γ-ray Spectroscopy of {sup 30}P via the {sup 28}Si({sup 3}He,pγ){sup 30}P Reaction

    Energy Technology Data Exchange (ETDEWEB)

    Mcneice, E.; Setoodehnia, K. [Department of Physics and Astronomy, McMaster University, Hamilton, ON L8S 4M1 (Canada); Singh, B., E-mail: ndgroup@mcmaster.ca [Department of Physics and Astronomy, McMaster University, Hamilton, ON L8S 4M1 (Canada); Abe, Y. [Institute of Physics, University of Tsukuba, Tennodai 1-1-1, Tsukuba, Ibaraki 305-8577 (Japan); Binh, D.N. [Center for Nuclear Study (CNS), the University of Tokyo, Wako Branch at RIKEN, Wako, Saitama 351-0198 (Japan); Chen, A.A.; Chen, J. [Department of Physics and Astronomy, McMaster University, Hamilton, ON L8S 4M1 (Canada); Cherubini, S. [INFN-Laboratori Nazionali del Sud and Dipartimento di Fisica ed Astronomia, Università di Catania, 95123 Catania (Italy); Center for Nuclear Study (CNS), the University of Tokyo, Wako Branch at RIKEN, Wako, Saitama 351-0198 (Japan); Fukuoka, S. [Institute of Physics, University of Tsukuba, Tennodai 1-1-1, Tsukuba, Ibaraki 305-8577 (Japan); Hashimoto, T. [Center for Nuclear Study (CNS), the University of Tokyo, Wako Branch at RIKEN, Wako, Saitama 351-0198 (Japan); Hayakawa, T. [Japan Atomic Energy Agency (JAEA), Tokai–mura, Ibaraki 319-1195 (Japan); Ishibashi, Y.; Ito, Y. [Institute of Physics, University of Tsukuba, Tennodai 1-1-1, Tsukuba, Ibaraki 305-8577 (Japan); Kahl, D. [Center for Nuclear Study (CNS), the University of Tokyo, Wako Branch at RIKEN, Wako, Saitama 351-0198 (Japan); Komatsubara, T. [Institute of Physics, University of Tsukuba, Tennodai 1-1-1, Tsukuba, Ibaraki 305-8577 (Japan); Kubono, S. [Nishina Center, the Institute of Physical and Chemical Research (RIKEN), Wako, Saitama 351-0198 (Japan); Moriguchi, T.; Nagae, D.; Nishikiori, R.; Niwa, T. [Institute of Physics, University of Tsukuba, Tennodai 1-1-1, Tsukuba, Ibaraki 305-8577 (Japan); and others

    2014-06-15

    The level structure of {sup 30}P up to 8.25 MeV was investigated via in-beam γ-ray spectroscopy using the {sup 28}Si({sup 3}He,pγ){sup 30}P reaction at 9 MeV at the University of Tsukuba Tandem Accelerator Complex in Japan. An energy level scheme was deduced from γ-γ coincidence measurements. 47 new transitions have been observed from the previously known states (mostly resonances), thereby reducing the uncertainties in the excitation energies of 17 states from 3 to 10 keV to values of < 1 keV. Furthermore, spin assignments based on measurements of γ-ray angular distributions and γ-γ directional correlation of oriented nuclei (DCO ratios) were made for several observed levels of {sup 30}P.

  2. Analysis of the fine structure of Sn11 +-Sn14 + ions by optical spectroscopy in an electron-beam ion trap

    Science.gov (United States)

    Windberger, A.; Torretti, F.; Borschevsky, A.; Ryabtsev, A.; Dobrodey, S.; Bekker, H.; Eliav, E.; Kaldor, U.; Ubachs, W.; Hoekstra, R.; Crespo López-Urrutia, J. R.; Versolato, O. O.

    2016-07-01

    We experimentally re-evaluate the fine structure of Sn11 +-Sn14 + ions. These ions are essential in bright extreme-ultraviolet (EUV) plasma-light sources for next-generation nanolithography, but their complex electronic structure is an open challenge for both theory and experiment. We combine optical spectroscopy of magnetic dipole M 1 transitions, in a wavelength range covering 260 to 780 nm, with charge-state selective ionization in an electron beam ion trap. Our measurements confirm the predictive power of ab initio calculations based on Fock space coupled cluster theory. We validate our line identification using semiempirical cowan calculations with adjustable wave-function parameters. Available Ritz combinations further strengthen our analysis. Comparison with previous work suggests that line identifications in the EUV need to be revisited.

  3. Electron emission yield and charging process of alkali-silicate glass submitted to an electron beam under the varying temperature condition

    Energy Technology Data Exchange (ETDEWEB)

    Belhaj, M., E-mail: Mohamed.Belhaj@onera.fr [ONERA - French Aerospace Lab, F-31055 Toulouse (France); Tondu, T.; Inguimbert, V. [ONERA - French Aerospace Lab, F-31055 Toulouse (France); Elsafi, B.; Fakhfakh, S. [LaMaCop, Faculte des Sciences de SFAX, Route Soukra Km 3, BP 1171, C.P 3000 Sfax (Tunisia); Jbara, O., E-mail: omar.jbara@univ-reims.fr [GRESPI/Materiaux Fonctionnels, UFR Sciences, BP 1039, 51687 Reims Cedex 2 (France)

    2012-01-01

    The electron emission due to electron impact of alkali-silicate glasses is measured with a technique based on the use of a Kelvin probe (KP method) and a pulsed electron beam. The KP method, allows a clear discrimination between the external and internal effects of charging process. The effect of the incident charge fluence, incident charge fluency and the temperature on the yield curve is investigated. It was found that, at room temperature as well as at 80 Degree-Sign C, electron emission varies with charge fluence. The effects of the temperature on charging mechanisms and charge transport characteristics of alkali-silicate glasses where also studied using the measurement of displacement and leakage currents under continuous electron irradiation in scanning electron microscope (SEM). The results clearly establish a correlation between charge carriers mobility and secondary electron emission yield. The enhancement of charge carrier mobility with increasing the temperature prevents the formation of a positive space charge (i.e. creation of positive ions and/or holes) that internally reduces the secondary electron (SE) emission. The higher is the temperature and the higher is the electron emission yield (EEY).

  4. Atomic emission spectroscopy

    Science.gov (United States)

    Andrew, K. H.

    1975-01-01

    The relationship between the Slater-Condon theory and the conditions within the atom as revealed by experimental data was investigated. The first spectrum of Si, Rb, Cl, Br, I, Ne, Ar, and Xe-136 and the second spectrum of As, Cu, and P were determined. Methods for assessing the phase stability of fringe counting interferometers and the design of an autoranging scanning system for digitizing the output of an infrared spectrometer and recording it on magnetic tape are described.

  5. Total and partial cross sections of the $^{112}$Sn($\\alpha,\\gamma$)$^{116}$Te reaction measured via in-beam $\\gamma$-ray spectroscopy

    CERN Document Server

    Netterdon, L; Scholz, P; Zilges, A

    2015-01-01

    An extended database of experimental data is needed to address uncertainties of the nuclear-physics input parameters for Hauser-Feshbach calculations. Especially $\\alpha$+nucleus optical model potentials at low energies are not well known. The in-beam technique with an array of high-purity germanium (HPGe) detectors was successfully applied to the measurement of absolute cross sections of an ($\\alpha$,$\\gamma$) reaction on a heavy nucleus at sub-Coulomb energies. The total and partial cross-section values were measured by means of in-beam $\\gamma$-ray spectroscopy. Total and partial cross sections were measured at four different $\\alpha$-particle energies from $E_\\alpha = 10.5$ MeV to $E_\\alpha = 12$ MeV. The measured total cross-section values are in excellent agreement with previous results obtained with the activation technique, which proves the validity of the applied method. The experimental data was compared to Hauser-Feshbach calculations using the nuclear reaction code TALYS. A modified version of the...

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

    Science.gov (United States)

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

    2015-01-01

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

  7. No Thermal Inversion and a Solar Water Abundance for the Hot Jupiter HD209458b from HST WFC3 Emission Spectroscopy

    CERN Document Server

    Line, Michael R; Bean, Jacob; Desert, Jean-Michel; Fortney, Jonathan J; Kreidberg, Laura; Madhusudhan, Nikku; Showman, Adam P; Diamond-Lowe, Hannah

    2016-01-01

    The nature of the vertical thermal structure of hot Jupiter atmospheres is one of the key questions raised by the characterization of transiting exoplanets over the last decade. There have been claims that many hot Jupiter's exhibit vertical profiles with increasing temperature with decreasing pressure in the infrared photosphere that leads to the reversal of molecular absorption bands into emission features (an inversion). However, these claims have been based on broadband photometry rather than the unambiguous identification of emission features with spectroscopy, and the chemical species that could cause the thermal inversions by absorbing stellar irradiation at high altitudes have not been identified despite extensive theoretical and observational effort. Here we present high precision HST WFC3 observations of the dayside emission spectrum of the hot Jupiter HD209458b; the first exoplanet suggested to have a thermal inversion. Our observations resolve a water band in absorption at 6.2 sigma confidence. Wh...

  8. k-space drift due to the density variation as a cause of electromagnetic emission generation of type III solar radio bursts by a non-gyrotropic electron beam

    Science.gov (United States)

    Tsiklauri, David; Schmitz, Holger

    2013-04-01

    It is widely accepted that there is a correlation between super-thermal electron beams and type III solar radio bursts. Whilst the correlation is an established fact, the actual mechanism that generates the type III burst emission is not yet fully determined. The main source of the uncertainty is current inability to send in-situ probes at distances 0.15 - 1.5Rsun from the solar surface (photosphere). The most widely accepted mechanism, that historically appeared first is the plasma emission. In plasma emission mechanism quasilinear theory, kinetic Fokker-Planck type equation for describing the dynamics of an electron beam is used, in conjunction with the spectral energy density evolutionary equations for Langmuir and ion-sound waves. Further, non-linear wave-wave interactions between Langmuir, ion-acoustic and EM waves produce emission at electron plasma frequency, ?pe or the second harmonic, 2?pe. A variant of the plasma emission mechanism is the stochastic growth theory, where density irregularities produce a random growth, in such a way that Langmuir waves are generated stochastically and quasilinear interactions within the Langmuir clumps cause the beam to fluctuate about marginal stability. The latter models have been used for producing the solar type III burst observable parameters. Other possible mechanisms include: linear mode conversion, antenna radiation and non-gyrotropic electron beam emission [1]. Recent works [2,3] elucidated further the non-gyrotropic electron beam emission, first proposed in Ref.[1]. In particular, the effect of electron beam pitch angle and density gradient on solar type III radio bursts was studied [2] and the role of electron cyclotron maser (ECM) emission with a possible mode coupling to the z-mode was explored [3]. In this contribution and paper [4], using large-scale Particle-In-Cell simulations, we explore the non-gyrotropic electron beam emission mechanism by studying the effects of electron beam kinetics and k-space drift

  9. Annihilation detector for an in-beam spectroscopy apparatus to measure the ground state hyperfine splitting of antihydrogen

    Science.gov (United States)

    Sauerzopf, Clemens; Capon, Aaron A.; Diermaier, Martin; Fleck, Markus; Kolbinger, Bernadette; Malbrunot, Chloé; Massiczek, Oswald; Simon, Martin C.; Vamosi, Stefan; Zmeskal, Johann; Widmann, Eberhard

    2017-02-01

    The matter-antimatter asymmetry observed in the universe today still lacks a quantitative explanation. One possible mechanism that could contribute to the observed imbalance is a violation of the combined Charge-, Parity- and Time symmetries (CPT). A test of CPT symmetry using anti-atoms is being carried out by the ASACUSA-CUSP collaboration at the CERN Antiproton Decelerator using a low temperature beam of antihydrogen-the most simple atomic system built only of antiparticles. While hydrogen is the most abundant element in the universe, antihydrogen is produced in very small quantities in a laboratory framework. A detector for in-beam measurements of the ground state hyperfine structure of antihydrogen has to be able to detect very low signal rates within high background. To fulfil this challenging task, a two layer barrel hodoscope detector was developed. It is built of plastic scintillators with double sided readout via Silicon Photomultipliers (SiPMs). The SiPM readout is done using novel, compact and cost efficient electronics that incorporate power supply, amplifier and discriminator on a single board. This contribution will evaluate the performance of the new hodoscope detector.

  10. Development of a multipurpose beam foil spectroscopy set-up for the low cross-section measurements

    Science.gov (United States)

    Sharma, Gaurav; Nandi, T.; Berry, H. G.; Puri, Nitin K.

    2016-08-01

    A multipurpose facility for low cross section measurements has been developed at Inter University Accelerator Centre, New Delhi, India. The facility consists of a multipurpose miniature chamber equipped with 1 m focal length normal incidence Monochromator and charge coupled device based detection system which has been aligned to realize the best resolution of the spectrometer. The chamber in this facility collects radiation 100 times more efficiently from the older system, without using any extra focusing mirror assembly. It is ensured to have the provision of mounting an X-ray detector and the spectrometer transverse to the beam direction simultaneously in the same chamber. The atomic spectroscopic studies can be performed by interaction of ions beams with both thin foil and gas targets. Provision for using photomultiplier tube instead of charge coupled device, is employed in the system depending on the condition of the source strength or other detection issues. We observed the essence of a very weak atomic phenomenon, a triply excited autoionizing forbidden transition, using the above facility to demonstrate its capability for measuring such low cross section phenomena. The present developed facility covers a large spectroscopic region from X-rays to the near infrared (0.1-10,000 Å).

  11. Admittance spectroscopy of Mg-doped GaN grown by molecular beam epitaxy using RF nitrogen sources

    CERN Document Server

    Kim, D J; Kim, K H; Bojarczuk, N A; Karasinski, J; Guha, S; Lee, H G

    1999-01-01

    Thermal activation energies of Mg in GaN grown using RF nitrogen source with varying Mg flux were examined using an admittance spectroscopy technique. There was no noticeable difference or trend in the activation energy with varying Mg flux. The thermal activation energy for GaN:Mg was approx 115 meV under the investigated Mg flux range. Negligible persistent photo-conductivity and yellow luminescence peak in PL observed in the samples suggest possible reduction of the thermal activation energies compared to the values in the literature.

  12. Beam-energy and system-size dependence of the space-time extent of the pion emission source produced in heavy ion collisions

    CERN Document Server

    Adare, A; Aidala, C; Ajitanand, N N; Akiba, Y; Akimoto, R; Al-Bataineh, H; Al-Ta'ani, H; Alexander, J; Alfred, M; Angerami, A; Aoki, K; Apadula, N; Aphecetche, L; Aramaki, Y; Armendariz, R; Aronson, S H; Asai, J; Asano, H; Aschenauer, E C; Atomssa, E T; Averbeck, R; Awes, T C; Azmoun, B; Babintsev, V; Bai, M; Baksay, G; Baksay, L; Baldisseri, A; Bandara, N S; Bannier, B; Barish, K N; Barnes, P D; Bassalleck, B; Basye, A T; Bathe, S; Batsouli, S; Baublis, V; Baumann, C; Baumgart, S; Bazilevsky, A; Beaumier, M; Beckman, S; Belikov, S; Belmont, R; Bennett, R; Berdnikov, A; Berdnikov, Y; Bickley, A A; Bing, X; Black, D; Blau, D S; Boissevain, J G; Bok, J S; Borel, H; Boyle, K; Brooks, M L; Bryslawskyj, J; Buesching, H; Bumazhnov, V; Bunce, G; Butsyk, S; Camacho, C M; Campbell, S; Castera, P; Chang, B S; Charvet, J -L; Chen, C -H; Chernichenko, S; Chi, C Y; Chiba, J; Chiu, M; Choi, I J; Choi, J B; Choi, S; Choudhury, R K; Christiansen, P; Chujo, T; Chung, P; Churyn, A; Chvala, O; Cianciolo, V; Citron, Z; Cleven, C R; Cole, B A; Comets, M P; Connors, M; Constantin, P; Csanád, M; Csörgő, T; Dahms, T; Dairaku, S; Danchev, I; Das, K; Datta, A; Daugherity, M S; David, G; Deaton, M B; DeBlasio, K; Dehmelt, K; Delagrange, H; Denisov, A; d'Enterria, D; Deshpande, A; Desmond, E J; Dharmawardane, K V; Dietzsch, O; Ding, L; Dion, A; Do, J H; Donadelli, M; Drapier, O; Drees, A; Drees, K A; Dubey, A K; Durham, J M; Durum, A; Dutta, D; Dzhordzhadze, V; D'Orazio, L; Edwards, S; Efremenko, Y V; Egdemir, J; Ellinghaus, F; Emam, W S; Engelmore, T; Enokizono, A; En'yo, H; Esumi, S; Eyser, K O; Fadem, B; Feege, N; Fields, D E; Finger, M; Jr., \\,; Fleuret, F; Fokin, S L; Fraenkel, Z; Frantz, J E; Franz, A; Frawley, A D; Fujiwara, K; Fukao, Y; Fusayasu, T; Gadrat, S; Gainey, K; Gal, C; Gallus, P; Garg, P; Garishvili, A; Garishvili, I; Ge, H; Giordano, F; Glenn, A; Gong, H; Gong, X; Gonin, M; Gosset, J; Goto, Y; de Cassagnac, R Granier; Grau, N; Greene, S V; Perdekamp, M Grosse; Gu, Y; Gunji, T; Guo, L; Guragain, H; Gustafsson, H -Å; Hachiya, T; Henni, A Hadj; Haegemann, C; Haggerty, J S; Hahn, K I; Hamagaki, H; Hamblen, J; Han, R; Han, S Y; Hanks, J; Harada, H; Hartouni, E P; Haruna, K; Hasegawa, S; Hashimoto, K; Haslum, E; Hayano, R; He, X; Heffner, M; Hemmick, T K; Hester, T; Hiejima, H; Hill, J C; Hobbs, R; Hohlmann, M; Hollis, R S; Holzmann, W; Homma, K; Hong, B; Horaguchi, T; Hori, Y; Hornback, D; Hoshino, T; Huang, J; Huang, S; Ichihara, T; Ichimiya, R; Ide, J; Iinuma, H; Ikeda, Y; Imai, K; Imazu, Y; Imrek, J; Inaba, M; Inoue, Y; Iordanova, A; Isenhower, D; Isenhower, L; Ishihara, M; Isobe, T; Issah, M; Isupov, A; Ivanischev, D; Ivanishchev, D; Jacak, B V; Javani, M; Jeon, S J; Jezghani, M; Jia, J; Jiang, X; Jin, J; Jinnouchi, O; Johnson, B M; Joo, E; Joo, K S; Jouan, D; Jumper, D S; Kajihara, F; Kametani, S; Kamihara, N; Kamin, J; Kaneta, M; Kaneti, S; Kang, B H; Kang, J H; Kang, J S; Kanou, H; Kapustinsky, J; Karatsu, K; Kasai, M; Kawall, D; Kawashima, M; Kazantsev, A V; Kempel, T; Key, J A; Khachatryan, V; Khanzadeev, A; Kihara, K; Kijima, K M; Kikuchi, J; Kim, B I; Kim, C; Kim, D H; Kim, D J; Kim, E; Kim, E -J; Kim, H -J; Kim, H J; Kim, K -B; Kim, M; Kim, S H; Kim, Y -J; Kim, Y K; Kinney, E; Kiriluk, K; Kiss, Á; Kistenev, E; Kiyomichi, A; Klatsky, J; Klay, J; Klein-Boesing, C; Kleinjan, D; Kline, P; Koblesky, T; Kochenda, L; Kochetkov, V; Kofarago, M; Komatsu, Y; Komkov, B; Konno, M; Koster, J; Kotchetkov, D; Kotov, D; Kozlov, A; Král, A; Kravitz, A; Krizek, F; Kubart, J; Kunde, G J; Kurihara, N; Kurita, K; Kurosawa, M; Kweon, M J; Kwon, Y; Kyle, G S; Lacey, R; Lai, Y S; Lajoie, J G; Lebedev, A; Lee, B; Lee, D M; Lee, J; Lee, K; Lee, K B; Lee, K S; Lee, M K; Lee, S H; Lee, S R; Lee, T; Leitch, M J; Leite, M A L; Leitgab, M; Leitner, E; Lenzi, B; Lewis, B; Li, X; Liebing, P; Lim, S H; Levy, L A Linden; Liška, T; Litvinenko, A; Liu, H; Liu, M X; Love, B; Luechtenborg, R; Lynch, D; Maguire, C F; Makdisi, Y I; Makek, M; Malakhov, A; Malik, M D; Manion, A; Manko, V I; Mannel, E; Mao, Y; Mašek, L; Masui, H; Masumoto, S; Matathias, F; McCumber, M; McGaughey, P L; McGlinchey, D; McKinney, C; Means, N; Meles, A; Mendoza, M; Meredith, B; Miake, Y; Mibe, T; Mignerey, A C; Mikeš, P; Miki, K; Miller, A J; Miller, T E; Milov, A; Mioduszewski, S; Mishra, D K; Mishra, M; Mitchell, J T; Mitrovski, M; Miyachi, Y; Miyasaka, S; Mizuno, S; Mohanty, A K; Montuenga, P; Moon, H J; Moon, T; Morino, Y; Morreale, A; Morrison, D P; Motschwiller, S; Moukhanova, T V; Mukhopadhyay, D; Murakami, T; Murata, J; Mwai, A; Nagae, T; Nagamiya, S; Nagata, Y; Nagle, J L; Naglis, M; Nagy, M I; Nakagawa, I; Nakagomi, H; Nakamiya, Y; Nakamura, K R; Nakamura, T; Nakano, K; Nattrass, C; Nederlof, A; Netrakanti, P K; Newby, J; Nguyen, M; Nihashi, M; Niida, T; Norman, B E; Nouicer, R; Novitzky, N; Nyanin, A S; O'Brien, E; Oda, S X; Ogilvie, C A; Ohnishi, H; Oka, M; Okada, K; Omiwade, O O; Onuki, Y; Koop, J D Orjuela; Oskarsson, A; Ouchida, M; Ozaki, H; Ozawa, K; Pak, R; Pal, D; Palounek, A P T; Pantuev, V; Papavassiliou, V; Park, B H; Park, I H; Park, J; Park, S; Park, S K; Park, W J; Pate, S F; Patel, L; Patel, M; Pei, H; Peng, J -C; Pereira, H; Perepelitsa, D V; Perera, G D N; Peresedov, V; Peressounko, D Yu; Perry, J; Petti, R; Pinkenburg, C; Pinson, R; Pisani, R P; Proissl, M; Purschke, M L; Purwar, A K; Qu, H; Rak, J; Rakotozafindrabe, A; Ravinovich, I; Read, K F; Rembeczki, S; Reuter, M; Reygers, K; Reynolds, D; Riabov, V; Riabov, Y; Richardson, E; Riveli, N; Roach, D; Roche, G; Rolnick, S D; Romana, A; Rosati, M; Rosen, C A; Rosendahl, S S E; Rosnet, P; Rowan, Z; Rubin, J G; Rukoyatkin, P; Ružička, P; Rykov, V L; Sahlmueller, B; Saito, N; Sakaguchi, T; Sakai, S; Sakashita, K; Sakata, H; Sako, H; Samsonov, V; Sano, M; Sano, S; Sarsour, M; Sato, S; Sato, T; Sawada, S; Schaefer, B; Schmoll, B K; Sedgwick, K; Seele, J; Seidl, R; Semenov, A Yu; Semenov, V; Sen, A; Seto, R; Sett, P; Sexton, A; Sharma, D; Shein, I; Shevel, A; Shibata, T -A; Shigaki, K; Shimomura, M; Shoji, K; Shukla, P; Sickles, A; Silva, C L; Silvermyr, D; Silvestre, C; Sim, K S; Singh, B K; Singh, C P; Singh, V; Skutnik, S; Slunečka, M; Soldatov, A; Soltz, R A; Sondheim, W E; Sorensen, S P; Soumya, M; Sourikova, I V; Sparks, N A; Staley, F; Stankus, P W; Stenlund, E; Stepanov, M; Ster, A; Stoll, S P; Sugitate, T; Suire, C; Sukhanov, A; Sumita, T; Sun, J; Sziklai, J; Tabaru, T; Takagi, S; Takagui, E M; Takahara, A; Taketani, A; Tanabe, R; Tanaka, Y; Taneja, S; Tanida, K; Tannenbaum, M J; Tarafdar, S; Taranenko, A; Tarján, P; Tennant, E; Themann, H; Thomas, T L; Timilsina, A; Todoroki, T; Togawa, M; Toia, A; Tojo, J; Tomášek, L; Tomášek, M; Torii, H; Towell, M; Towell, R; Towell, R S; Tram, V-N; Tserruya, I; Tsuchimoto, Y; Tsuji, T; Vale, C; Valle, H; van Hecke, H W; Vargyas, M; Vazquez-Zambrano, E; Veicht, A; Velkovska, J; Vértesi, R; Vinogradov, A A; Virius, M; Vossen, A; Vrba, V; Vznuzdaev, E; Wagner, M; Walker, D; Wang, X R; Watanabe, D; Watanabe, K; Watanabe, Y; Watanabe, Y S; Wei, F; Wei, R; Wessels, J; Whitaker, S; White, S N; Winter, D; Wolin, S; Wood, J P; Woody, C L; Wright, R M; Wysocki, M; Xia, B; Xie, W; Xue, L; Yalcin, S; Yamaguchi, Y L; Yamaura, K; Yang, R; Yanovich, A; Yasin, Z; Ying, J; Yokkaichi, S; Yoon, I; You, Z; Young, G R; Younus, I; Yushmanov, I E; Zajc, W A; Zaudtke, O; Zelenski, A; Zhang, C; Zhou, S; Zimányi, J; Zolin, L

    2014-01-01

    Two-pion interferometry measurements are used to extract the Gaussian radii $R_{{\\rm out}}$, $R_{{\\rm side}}$, and $R_{{\\rm long}}$, of the pion emission sources produced in Cu$+$Cu and Au$+$Au collisions at several beam collision energies $\\sqrt{s_{_{NN}}}$ at PHENIX. The extracted radii, which are compared to recent STAR and ALICE data, show characteristic scaling patterns as a function of the initial transverse size $\\bar{R}$ of the collision systems and the transverse mass $m_T$ of the emitted pion pairs, consistent with hydrodynamiclike expansion. Specific combinations of the three-dimensional radii that are sensitive to the medium expansion velocity and lifetime, and the pion emission time duration show nonmonotonic $\\sqrt{s_{_{NN}}}$ dependencies. The nonmonotonic behaviors exhibited by these quantities point to a softening of the equation of state that may coincide with the critical end point in the phase diagram for nuclear matter.

  13. On the excess photon noise in single-beam measurements with photo-emissive and photo-conductive cells

    NARCIS (Netherlands)

    Alkemade, C.T.J.

    1959-01-01

    In this paper the so-called excess photon noise is theoretically considered with regard to noise power measurements with a single, illumined photo-emissive or photo-conductive cell. Starting from a modification of Mandel's stochastic association of the emission of photo-electrons with wave intensity

  14. Simulating Cometary and Stellar X-ray Emission in the Laboratory Using Microcalorimeters and an Electron Beam Ion Trap

    Science.gov (United States)

    Brown, G. V.; Beiersdorfer, P.; Chen, H.; Graf, A.; May, M.; Terracol, S.; Thorn, D.; Boyce, K. R.; Cottam, J.; Gendreau, K. C.; Kahn, S. M.; Kelley, R. L.; Kilbourne, C. A.; Porter, F. S.; Szymkowiak, A. E.

    2004-10-01

    The mixing of atomic and macroscopic processes taking place in non-terrestrial objects creates complex, dynamic, and intriguing environments. High resolution x-ray spectra from these sources measured by satellites such as Chandra, XMM-Newton, and the Solar Maximum Mission provide a means for understanding the physics governing these sources. Laboratory measurements of the atomic processes have proved crucial to the interpretation of these spectra. For example using the LLNL electron beam ion traps EBIT-I & EBIT-II a detailed study of the x-ray spectrum of Fe XVII has been conducted addressing the large ratio predicted by theory compared to observations of considerably smaller values of the relative intensity of the 2p-3d 1P1 resonant to the 3D1 intercombination line. The difference was often attributed to opacity effects. However, laboratory measurements in the optically thin limit agree with observations demonstrating that the prediction is too large and opacity need not be invoked. The laboratory results thus provide a benchmark in the optically thin limit for accurate estimates of opacity effects . To uncover the source of the discrepancy between theory and observation, we have performed a series of experiments that successively uncovered more details about the Fe XVII lines produced in coronal plasmas. Most recently, we used a 32 channel array microcalorimeter from the Astro-E x-ray satellite program to measure the excitation cross section of various Fe XVII lines in the laboratory. These measurements resolve long-standing issues thought to be associated with non-equilibrium processes. We have also used the Astro-E microcalorimeter, and more recently its upgrade from the Astro-E2 project, and the magnetic trapping mode of EBIT-I to accurately measure x-ray emission from charge exchange recombination and to simulate the x-ray line production process in comets. Using only the laboratory measurements, we fit the moderate resolution x-ray spectrum from the comet C

  15. Characterization of ion-irradiated ODS Fe–Cr alloys by doppler broadening spectroscopy using a positron beam

    Energy Technology Data Exchange (ETDEWEB)

    Parente, P.; Leguey, T. [Departamento de Física and IAAB, Universidad Carlos III de Madrid, 28911 Leganés (Spain); Castro, V. de, E-mail: vanessa.decastro@uc3m.es [Departamento de Física and IAAB, Universidad Carlos III de Madrid, 28911 Leganés (Spain); Gigl, T.; Reiner, M.; Hugenschmidt, C. [FRM II and Physics Department, Technische Universität München, 85747 Garching (Germany); Pareja, R. [Departamento de Física and IAAB, Universidad Carlos III de Madrid, 28911 Leganés (Spain)

    2015-09-15

    The damage profile of oxide dispersion strengthened steels after single-, or simultaneous triple-ion irradiation at different conditions has been characterized using a low energy positron beam in order to provide information on microstructural changes induced by irradiation. Doppler broadening and coincident Doppler broadening measurements of the positron annihilation line have been performed on different Fe–Cr–(W,Ti) alloys reinforced with Y{sub 2}O{sub 3}, to identify the nature and stability of irradiation-induced open-volume defects and their possible association with the oxide nanoparticles. It was found that irradiation induced vacancy clusters are associated with Cr atoms. The results are of highest interest for modeling the damage induced by 14 MeV neutrons in reduced activation Fe–Cr alloys relevant for fusion devices.

  16. Characterization of metallic nanoparticles by high-resolution X-ray absorption and X-ray emission spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Kuehn, Timna-Josua

    2012-03-15

    In almost all areas of technology, metallic nanoparticles are of interest due to their special thermal, electronic, magnetic and optical properties. Their special properties are mainly due to their small size which implies the relevance of quantum effects as well as the significance of the surface: For 2 nm nanoparticles, the surface-to-volume ratio is already 1:1. However, the identification of surface-to-volume interactions - that are responsible for the new properties - is a difficult task due to the small size that inhibits a lot of 'standard' techniques to be applicable. Here X-ray absorption/emission spectroscopy (XAS/XES) is a favorable tool for the characterization of nanoparticles, independent on size, degree of crystallinity and shape/condition of the surface. Using XAS, a tempered nanosized Co{sub 3}Pt/C catalyst have been investigated. Its outstanding oxygen-reduction reaction (ORR) properties in a fuel cell could be related to a lowered Pt 5d-band center connected to a tightened Pt-Pt bonding distance, leading to a weakening of the oxygen adsorption strength so that the ORR may proceed faster. One drawback remains, however, as the properties found by (standard) XAS are summed up for different chemical environments of the chosen element. Thus, no distinction can be made between, e.g., the pure metal in a nanoparticles' interior and the ligated metal in the outer shells or surface. Here, high-resolution fluorescence-detected XAS (HRFD-XAS) provides additional opportunities as, due to its chemical sensitivity, it leads to site-selective XAS. For a system of 6 nm sized Co nanoparticles, build up of a metallic core surrounded by a protecting shell, that resulted from the 'smooth oxidation' process, this technique of site-selective XAS was proven to be applicable. For the first time, the interior and outer shell of a metallic nanoparticle could be characterized separately. In particular, the Co-hcp phase could be determined for the

  17. High-Flux Femtosecond X-Ray Emission from Controlled Generation of Annular Electron Beams in a Laser Wakefield Accelerator.

    Science.gov (United States)

    Zhao, T Z; Behm, K; Dong, C F; Davoine, X; Kalmykov, S Y; Petrov, V; Chvykov, V; Cummings, P; Hou, B; Maksimchuk, A; Nees, J A; Yanovsky, V; Thomas, A G R; Krushelnick, K

    2016-08-26

    Annular quasimonoenergetic electron beams with a mean energy in the range 200-400 MeV and charge on the order of several picocoulombs were generated in a laser wakefield accelerator and subsequently accelerated using a plasma afterburner in a two-stage gas cell. Generation of these beams is associated with injection occurring on the density down ramp between the stages. This well-localized injection produces a bunch of electrons performing coherent betatron oscillations in the wakefield, resulting in a significant increase in the x-ray yield. Annular electron distributions are detected in 40% of shots under optimal conditions. Simultaneous control of the pulse duration and frequency chirp enables optimization of both the energy and the energy spread of the annular beam and boosts the radiant energy per unit charge by almost an order of magnitude. These well-defined annular distributions of electrons are a promising source of high-brightness laser plasma-based x rays.

  18. The Grism Lens-Amplified Survey from Space (GLASS). III. A census of Ly\\alpha\\ Emission at $z\\gtrsim$7 from HST Spectroscopy

    CERN Document Server

    Schmidt, K B; Bradač, M; Vulcani, B; Huang, K -H; Hoag, A; Maseda, M; Guaita, L; Pentericci, L; Brammer, G B; Dijkstra, M; Dressler, A; Fontana, A; Henry, A L; Jones, T A; Mason, C; Trenti, M; Wang, X

    2015-01-01

    [abbreviated] We present a census of Ly\\alpha\\ emission at $z\\gtrsim7$ utilizing deep near infrared HST grism spectroscopy from the first six completed clusters of the Grism Lens-Amplified Survey from Space (GLASS). In 24/159 photometrically selected galaxies we detect emission lines consistent with Ly\\alpha\\ in the GLASS spectra. Based on the distribution of signal-to-noise ratios and on simulations we expect the completeness and the purity of the sample to be 40-100% and 60-90%, respectively. For the objects without detected emission lines we show that the observed (not corrected for lensing magnification) 1$\\sigma$ flux limits reaches $5\\times10^{-18}$erg/s/cm$^{2}$ per position angle over the full wavelength range of GLASS (0.8-1.7$\\mu$m). Based on the conditional probability of Ly\\alpha\\ emission measured from the ground at $z\\sim7$ we would have expected 12-18 Ly\\alpha\\ emitters. This is consistent with the number of detections, within the uncertainties, confirming the drop in Ly\\alpha\\ emission with re...

  19. VLT/XSHOOTER & Subaru/MOIRCS Spectroscopy of HUDF-YD3: No Evidence for Lyman-alpha Emission at z=8.55

    CERN Document Server

    Bunker, Andrew J; Wilkins, Stephen M; Stanway, Elizabeth R; Lorenzoni, Silvio; Lacy, Mark; Jarvis, Matt J; Hickey, Samantha

    2013-01-01

    We present spectroscopic observations with VLT/XSHOOTER and Subaru/MOIRCS of a relatively bright Y-band drop-out galaxy in the Hubble Ultra Deep Field, first selected by Bunker et al. (2010), McLure et al. (2010) and Bouwens et al. (2010) to be a likely z~8-9 galaxy on the basis of its colours in the HST ACS and WFC3 images. This galaxy, HUDF.YD3 (also known as UDFy-38135539) has been targetted for VLT/SINFONI integral field spectroscopy by Lehnert et al. (2010), who published a candidate Lyman-alpha emission line at z=8.55 from this source. In our independent spectroscopy using two different infrared spectrographs (5 hours with VLT/XSHOOTER and 11 hours with Subaru/MOIRCS) we are unable to reproduce this line. We do not detect any emission line at the spectral and spatial location reported in Lehnert et al. (2010), despite the expected signal in our combined MOIRCS & XSHOOTER data being 5-sigma. The line emission also seems to be ruled out by the faintness of this object in recently extremely deep F105W ...

  20. Multi-Beam Optical Tweezers

    DEFF Research Database (Denmark)

    2003-01-01

    A set of multi-beam electromagnetic tweezers is provided comprising a multi-beam generator for emission of a plurality of electromagnetic beams, at least some of the electromagnetic beams intersecting each other, or, having an individually controlled polarization whereby the position and/or angular...... orientation of a plurality of micro-objects may be individually controlled.A set of multi-beam electromagnetic tweezers is provided comprising a multi-beam generator for emission of a plurality of electromagnetic beams, at least some of the electromagnetic beams intersecting each other, or, having...

  1. Probing Field Emission from Boron Carbide Nanowires

    Institute of Scientific and Technical Information of China (English)

    TIAN Ji-Fa; GAO Hong-Jun; BAO Li-Hong; WANG Xing-Jun; HUI Chao; LIU Fei; LI Chen; SHEN Cheng-Min; WANG Zong-Li; GU Chang-Zhi

    2008-01-01

    High density boron carbide nanowires are grown by an improved carbon thermal reduction technique. Transmission electron microscopy and electron energy lose spectroscopy of the sample show that the synthesized nanowires are B4 C with good crystallization. The field emission measurement for an individual boron nanowire is performed by using a Pt tip installed in the focused ion beam system. A field emission current with enhancement factor of 106 is observed and the evolution process during emission is also carefully studied. Furthermore, a two-step field emission with stable emission current density is found from the high-density nanowire film. Our results together suggest that boron carbide nanowires are promising candidates for electron emission nanodevices.

  2. Electron Emission And Beam Generation Using Ferroelectric Cathodes (electron Beam Generation, Lead Lanthanum Zicronate Titanate, High Power Traveling Wave Tube Amplfier)

    CERN Document Server

    Flechtner, D D

    1999-01-01

    In 1989, researchers at CERN published the discovery of significant electron emission (1– 100 A/cm2) from Lead- Lanthanum-Zirconate-Titanate (PLZT). The publication of these results led to international interest in ferroelectric cathodes studies for use in pulsed power devices. At Cornell University in 1991, experiments with Lead-Zirconate-Titanate (PZT) compositions were begun to study the feasibility of using this ferroelectric material as a cathode in the electron gun section of High Power Traveling Wave Tube Amplifier Experiments. Current-voltage characteristics were documented for diode voltages ranging from 50– 500,000 V with anode cathode gaps of.5– 6 cm. A linear current-voltage relation was found for voltages less than 50 kV. For diode voltages ≥ 200 kV, a typical Child-Langmuir V3/2 dependence was observed...

  3. Coupling creep and damage in concrete under high sustained loading: Experimental investigation on bending beams and application of Acoustic Emission technique

    Directory of Open Access Journals (Sweden)

    Grondin F.

    2010-06-01

    had a strengthening effect on concrete, probably because of the consolidation of the hardened cement paste. The influence of creep on fracture energy, fracture toughness, and characteristic length of concrete is also studied. The fracture energy and the characteristic length of concrete increases slightly when creep occurs prior to failure and the size of the fracture process zone increases too. The load-CMOD relationship is linear in the ascending portion and gradually drops off after the peak value in the descending portion. The length of the tail end portion of the softening curve increases with beams subjected to creep. Relatively more ductile fracture behavior was observed with beams subjected to creep. The contribution of non-destructive and instrumental investigation methods is currently exploited to check and measure the evolution of some negative structural phenomena, such as micro-and macro-cracking, finally resulting in a creep-like behaviour. Among these methods, the non-destructive technique based on acoustic Emission proves to be very effective, especially to check and measure micro-cracking that takes place inside a structure under mechanical loading. Thus as a part of the investigation quantitative acoustic emission techniques were applied to investigate microcracking and damage localization in concrete beams. The AE signals were captured with the AE WIN software and further analyzed with Noesis software analysis of acoustic emission data. AE waveforms were generated as elastic waves in concrete due to crack nucleation. And a multichannel data acquisition system was used to record the AE waveforms. During the three point bending tests, quantitative acoustic emission (AE techniques were used to monitor crack growth and to deduce micro fracture mechanics in concrete beams before and after creep. Several specimens are experimented in order to match each cluster with corresponding damage mechanism of the material under loading. At the same time acoustic

  4. Simultaneous Counter-Ion Co-Deposition a Technique Enabling Matrix Isolation Spectroscopy Studies Using Low-Energy Beams of Mass-Selected Ions

    Science.gov (United States)

    Ludwig, Ryan M.; Moore, David T.

    2014-06-01

    Matrix isolation spectroscopy was first developed in Pimentel's group during the 1950's to facilitate spectroscopic studies of transient species. Cryogenic matrices of condensed rare gases provide an inert chemical environment with facile energy dissipation and are transparent at all wavelengths longer than vacuum UV, making them ideal for studying labile and reactive species such as radicals, weakly bound complexes, and ions. Since frozen rare gases are poor electrolytes, studies of ions require near-equal populations of anions and cations in order to stabilize the number densities required for spectroscopic experiments. Many techniques for generation of ions for using in matrix isolation studies satisfy this criterion intrinsically, however when ion beams generated in external sources are deposited, the counter-ions typically arise via secondary processes that are at best loosely controlled. It has long been recognized that it would be desirable to stabilize deposition of mass-selected ions generated in an external source using simultaneous co-deposition of a beam of counter-ions, however previous attempts to achieve this have been reported as unsuccessful. The Moore group at Lehigh has demonstrated successful experiments of this type, using mass-selected anions generated from a metal cluster source, co-deposited with a balanced current of cations generated in a separate electron ionization source. This talk will focus on the details of the technique, and present some results from proof-of-concept studies on anionic copper carbonyl complexes formed in argon matrices following co-deposition of Cu- with Ar+ or Kr+. Funding support from NSF CAREER Award CHE-0955637 is gratefully acknowledged. Whittle et al., J. Chem. Phys. 22, p.1943 (1954); Becker et al., J. Chem. Phys. 25, p.224 (1956). Godbout et al., J. Chem. Phys. 96, p.2892 (1996). Sabo et al., Appl. Spectrosc. 45, p. 535 (1991).

  5. ESTIMATION OF METHANE EMISSIONS FROM A SURFACE COAL MINE USING OPEN-PATH FTIR SPECTROSCOPY AND MODELING TECHNIQUES

    Science.gov (United States)

    A new measurements methodology has been developed which allows the rapid and efficient measurement of methane (CH4) emissions from surface coal mines. An initial field trial of this methodology has been completed, and results from the field trial revealed that emissions from one ...

  6. Noninvasive express diagnostics of pulmonary diseases based on control of patient's gas emission using methods of IR and terahertz laser spectroscopy

    Science.gov (United States)

    Starikova, M. K.; Bulanova, A. A.; Bukreeva, E. B.; Karapuzikov, A. A.; Karapuzikov, A. I.; Kistenev, Y. V.; Klementyev, V. M.; Kolker, D. B.; Kuzmin, D. A.; Nikiforova, O. Y.; Ponomarev, Yu. N.; Sherstov, I. V.; Boyko, A. A.

    2013-11-01

    Pulmonary diseases diagnostics always occupies one of the key positions in medicine practices. A large variety of high technology methods are used today, but none of them cannot be used for early screening of pulmonary diseases. We discuss abilities of methods of IR and terahertz laser spectroscopy for noninvasive express diagnostics of pulmonary diseases on a base of analysis of absorption spectra of patient's gas emission, in particular, exhaled air. Experience in the field of approaches to experimental data analysis and hard-ware realization of gas analyzers for medical applications is also discussed.

  7. LASER ABLATION-INDUCTIVELY COUPLED PLASMA-ATOMIC EMISSION SPECTROSCOPY STUDY AT THE 222-S LABORATORY USING HOT-CELL GLOVE BOX PROTOTYPE SYSTEM

    Energy Technology Data Exchange (ETDEWEB)

    SEIDEL CM; JAIN J; OWENS JW

    2009-02-23

    This report describes the installation, testing, and acceptance of the Waste Treatment and Immobilization Plant (WTP) procured laser ablation-inductively coupled plasma-atomic emission spectroscopy (LA-ICP-AES) system for remotely analyzing high-level waste (HLW) samples in a hot cell environment. The work was completed by the Analytical Process Development (APD) group in accordance with Task Order 2005-003; ATS MP 1027, Management Plan for Waste Treatment Plant Project Work Performed by Analytical Technical Services. The APD group at the 222-S Laboratory demonstrated acceptable turnaround time (TAT) and provide sufficient data to assess sensitivity, accuracy, and precision of the LA-ICP-AES method.

  8. Infrared heterodyne spectroscopy of astronomical and laboratory sources at 8.5 micron. [absorption line profiles of nitrogen oxide and black body emission from Moon and Mars

    Science.gov (United States)

    Mumma, M.; Kostiuk, T.; Cohen, S.; Buhl, D.; Vonthuna, P. C.

    1974-01-01

    The first infrared heterodyne spectrometer using tuneable semiconductor (PbSe) diode lasers has been constructed and was used near 8.5 micron to measure absorption line profiles of N2O in the laboratory and black body emission from the Moon and from Mars. Spectral information was recorded over a 200 MHz bandwidth using an 8-channel filter bank. The resolution was 25 MHz and the minimum detectable (black body) power was 1 x 10 to the minus 16th power watts for 8 minutes of integration. The results demonstrate the usefulness of heterodyne spectroscopy for the study of remote and local sources in the infrared.

  9. Scanning Tunneling Microscopy and Spectroscopy of Air Exposure Effects on Molecular Beam Epitaxy Grown WSe2 Monolayers and Bilayers.

    Science.gov (United States)

    Park, Jun Hong; Vishwanath, Suresh; Liu, Xinyu; Zhou, Huawei; Eichfeld, Sarah M; Fullerton-Shirey, Susan K; Robinson, Joshua A; Feenstra, Randall M; Furdyna, Jacek; Jena, Debdeep; Xing, Huili Grace; Kummel, Andrew C

    2016-04-26

    The effect of air exposure on 2H-WSe2/HOPG is determined via scanning tunneling microscopy (STM). WSe2 was grown by molecular beam epitaxy on highly oriented pyrolytic graphite (HOPG), and afterward, a Se adlayer was deposited in situ on WSe2/HOPG to prevent unintentional oxidation during transferring from the growth chamber to the STM chamber. After annealing at 773 K to remove the Se adlayer, STM images show that WSe2 layers nucleate at both step edges and terraces of the HOPG. Exposure to air for 1 week and 9 weeks caused air-induced adsorbates to be deposited on the WSe2 surface; however, the band gap of the terraces remained unaffected and nearly identical to those on decapped WSe2. The air-induced adsorbates can be removed by annealing at 523 K. In contrast to WSe2 terraces, air exposure caused the edges of the WSe2 to oxidize and form protrusions, resulting in a larger band gap in the scanning tunneling spectra compared to the terraces of air-exposed WSe2 monolayers. The preferential oxidation at the WSe2 edges compared to the terraces is likely the result of dangling edge bonds. In the absence of air exposure, the dangling edge bonds had a smaller band gap compared to the terraces and a shift of about 0.73 eV in the Fermi level toward the valence band. However, after air exposure, the band gap of the oxidized WSe2 edges became about 1.08 eV larger than that of the WSe2 terraces, resulting in the electronic passivation of the WSe2.

  10. Dielectric spectroscopy of electron beam deposited yttrium oxide films examined in metal–insulator–metal sandwich type structures

    Energy Technology Data Exchange (ETDEWEB)

    Wiktorczyk, Tadeusz, E-mail: Tadeusz.Wiktorczyk@pwr.wroc.pl; Biegański, Piotr

    2014-01-31

    This report describes the dielectric properties of electron-beam deposited Y{sub 2}O{sub 3} thin films examined in metal–insulator–metal-type structures fabricated onto quartz substrates. The dielectric measurements have been carried out in the frequency domain from 10 mHz to 10 MHz, with a frequency response analyser. Frequency characteristics of the complex capacitance, as well as Cole–Cole and Nyquist graphs, have been presented and discussed for the temperature range 398–523 K. The results have been analyzed in terms of equivalent circuit models containing resistance–capacitance and constant phase elements (CPE). We have determined the values of the resistance, capacitance and CPE, which characterize the Y{sub 2}O{sub 3} film and near-electrode regions. It has been shown that for high frequencies/low temperatures the dielectric properties are connected with Y{sub 2}O{sub 3} film, while for low frequencies/high temperatures the dielectric response is dominated by the near-electrode regions. In the frequency range 0.1–10 MHz the important contribution of series resistance of electrodes and leads has been observed. - Highlights: • We examine the Al/Y{sub 2}O{sub 3}/Al thin film capacitors for frequency range 10 mHz–10 MHz. • The dielectric data are assigned to Y{sub 2}O{sub 3} and to metal/insulator interfaces. • The capacitance, resistance and constant phase elements describe their properties. • The values of these elements are estimated for temperatures from 398 K to 523 K.

  11. Simulating Valence-to-Core X-ray Emission Spectroscopy of Transition Metal Complexes with Time-Dependent Density Functional Theory

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yu; Mukamel, Shaul; Khalil, Munira; Govind, Niranjan

    2015-11-09

    Valence-to-core (VtC) X-ray emission spectroscopy (XES) has emerged as a power- ful technique for the structural characterization of complex organometallic compounds in realistic environments. Since the spectrum represents electronic transitions from the ligand molecular orbitals to the core holes of the metal centers, the approach is more chemically sensitive to the metal-ligand bonding character compared with con- ventional X-ray absorption techniques. In this paper we study how linear-response time-dependent density functional theory (LR-TDDFT) can be harnessed to simulate K-edge VtC X-ray emission spectra reliably. LR-TDDFT allows one to go beyond the single-particle picture that has been extensively used to simulate VtC-XES. We con- sider seven low- and high-spin model complexes involving chromium, manganese and iron transition metal centers. Our results are in good agreement with experiment.

  12. Controlled variation of the information depth by angle dependent soft X-ray emission spectroscopy: A study on polycrystalline Cu(In,Ga)Se 2

    Science.gov (United States)

    Mönig, H.; Lauermann, I.; Grimm, A.; Camus, C.; Kaufmann, C. A.; Pistor, P.; Jung, Ch.; Kropp, T.; Lux-Steiner, M. C.; Fischer, Ch.-H.

    2008-12-01

    Angle dependent X-ray emission spectroscopy (AXES) is introduced as a tool for depth dependent composition analysis. A controlled variation of the information depth is demonstrated by changing the geometry from grazing exit to grazing incidence geometry. First results are presented from Cu(In,Ga)Se 2 (CIGSe)-based polycrystalline thin film solar cell bi-layer components. A mathematical model explains changes in relative intensity due to the absorption and emission behavior of thin CdS and Zn(S,O) cover layers. The fact that the presented data can be modelled by ideal bi-layer structures, provides both, proof of concept in general and the proof of applicability to the relatively rough layered structures based on CIGSe. In bare CIGSe a homogeneous distribution of Cu and Ga is found in a depth range between 22 and 470 nm.

  13. Emission spectroscopy of IR laser-induced processes in ultra-dense deuterium D(0): Rotational transitions in D(0) with spin values s = 2, 3 and 4

    Science.gov (United States)

    Holmlid, Leif

    2017-02-01

    The emission spectrum induced in ultra-dense deuterium D(0) by a 1064 nm pulsed YAG laser with 0.4 J pulses is strongly dependent on the amount of D(0) formed. With D2 pressure below 10-2 mbar at the D(0) generator and no D(0) layer on the metal surface, line spectra can be observed with numerous lines due to metal and gas atoms. When a D(0) layer exists on the generator surface, these lines disappear. A different pattern of emission lines and bands is then found. Several peaks are observed which agree well with the rotational transitions of rotating D-D pairs in D(0) from theory. The peak widths are approximately 20 cm-1. A prominent peak at 760 nm corresponds to spin state s = 3 in D(0) from a rotational transition J = 1 → 0. This gives an experimental D-D distance in this state of 5.052 ± 0.003 pm that is only 0.25% larger than predicted by theory and calculations. The existence of these rotational lines strongly supports the cluster model of D(0) described previously. At a few hundred mbar pressure, a red-emitting apparently self-focused beam is formed by the laser beam. The expected Balmer lines are weak or absent.

  14. Quantification of fluorine traces in solid samples using CaF molecular emission bands in atmospheric air Laser-Induced Breakdown Spectroscopy

    Science.gov (United States)

    Alvarez-Llamas, C.; Pisonero, J.; Bordel, N.

    2016-09-01

    Direct solid determination of trace amounts of fluorine using Laser-Induced Breakdown Spectroscopy (LIBS) is a challenging task due to the low excitation efficiency of this element. Several strategies have been developed to improve the detection capabilities, including the use of LIBS in a He atmosphere to enhance the signal to background ratios of F atomic emission lines. An alternative method is based on the detection of the molecular compounds that are formed with fluorine in the LIBS plasma. In this work, the detection of CaF molecular emission bands is investigated to improve the analytical capabilities of atmospheric air LIBS for the determination of fluorine traces in solid samples. In particular, Cu matrix samples containing different fluorine concentration (between 50 and 600 μg/g), and variable amounts of Ca, are used to demonstrate the linear relationships between CaF emission signal and F concentration. Limits of detection for fluorine are improved by more than 1 order of magnitude using CaF emission bands versus F atomic lines, in atmospheric-air LIBS. Furthermore, a toothpaste powder sample is used to validate this analytical method. Good agreement is observed between the nominal and the predicted fluorine mass-content.

  15. Remote sensing of temperature and concentration profiles of a gas jet by coupling infrared emission spectroscopy and LIDAR for characterization of aircraft engine exhaust

    Science.gov (United States)

    Offret, J.-P.; Lebedinsky, J.; Navello, L.; Pina, V.; Serio, B.; Bailly, Y.; Hervé, P.

    2015-05-01

    Temperature data play an important role in the combustion chamber since it determines both the efficiency and the rate of pollutants emission of engines. Air pollution problem concerns the emissions of gases such as CO, CO2, NO, NO2, SO2 and also aerosols, soot and volatile organic compounds. Flame combustion occurs in hostile environments where temperature and concentration profiles are often not easy to measure. In this study, a temperature and CO2 concentration profiles optical measurement method, suitable for combustion analysis, is discussed and presented. The proposed optical metrology method presents numerous advantages when compared to intrusive methods. The experimental setup comprises a passive radiative emission measurement method combined with an active laser-measurement method. The passive method is based on the use of gas emission spectroscopy. The experimental spectrometer device is coupled with an active method. The active method is used to investigate and correct complex flame profiles. This method similar to a LIDAR (Light Detection And Ranging) device is based on the measurement of Rayleigh scattering of a short laser pulse recorded using a high-speed streak camera. The whole experimental system of this new method is presented. Results obtained on a small-scale turbojet are shown and discussed in order to illustrate the potentials deliver by the sophisticated method. Both temperature and concentration profiles of the gas jet are presented and discussed.

  16. AKARI near-infrared spectroscopy of the extended green object G318.05+0.09: Detection of CO fundamental ro-vibrational emission

    CERN Document Server

    Onaka, Takashi; Sakon, Itsuki; Ardaseva, Aleksandra

    2016-01-01

    We present the results of near-infrared (2.5--5.4um) long-slit spectroscopy of the extended green object (EGO) G318.05+0.09 with AKARI. Two distinct sources are found in the slit. The brighter source has strong red continuum emission with H2O ice, CO2 ice, and CO gas and ice absorption features at 3.0, 4.25um, 4.67um, respectively, while the other greenish object shows peculiar emission that has double peaks at around 4.5 and 4.7um. The former source is located close to the ultra compact HII region IRAS 14498-5856 and is identified as an embedded massive young stellar object. The spectrum of the latter source can be interpreted by blue-shifted (-3000 ~ -6000km/s) optically-thin emission of the fundamental ro-vibrational transitions (v=1-0) of CO molecules with temperatures of 12000--3700K without noticeable H2 and HI emission. We discuss the nature of this source in terms of outflow associated with the young stellar object and supernova ejecta associated with a supernova remnant.

  17. The Number Density Evolution of Extreme Emission Line Galaxies in 3D-HST: Results from a Novel Automated Line Search Technique for Slitless Spectroscopy

    CERN Document Server

    Maseda, Michael V; Rix, Hans-Walter; Momcheva, Ivelina; Brammer, Gabriel B; Franx, Marijn; Lundgren, Britt F; Skelton, Rosalind E; Whitaker, Katherine E

    2016-01-01

    The multiplexing capability of slitless spectroscopy is a powerful asset in creating large spectroscopic datasets, but issues such as spectral confusion make the interpretation of the data challenging. Here we present a new method to search for emission lines in the slitless spectroscopic data from the 3D-HST survey utilizing the Wide-Field Camera 3 on board the Hubble Space Telescope. Using a novel statistical technique, we can detect compact (extended) emission lines at 90% completeness down to fluxes of 1.5 (3.0) times 10^{-17} erg/s/cm^2, close to the noise level of the grism exposures, for objects detected in the deep ancillary photometric data. Unlike previous methods, the Bayesian nature allows for probabilistic line identifications, namely redshift estimates, based on secondary emission line detections and/or photometric redshift priors. As a first application, we measure the comoving number density of Extreme Emission Line Galaxies (restframe [O III] 5007 equivalent widths in excess of 500 Angstroms)...

  18. Symposium on atomic spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    1979-01-01

    Topics covered by the conference include: fast beam spectroscopy; astrophysical and other spectra; highly ionized spectroscopy; complex spectra; rydberg levels; fine structure, hyperfine structure and isotope shift; lineshapes; lifetimes, oscillator strengths and Einstein coefficients; and spectroscopy with lasers. Abstracts of the conference papers are presented. (GHT)

  19. Heterogeneity in optical properties of near white-light emissive europium complex species revealed by spectroscopy of single nanoaggregates

    Science.gov (United States)

    Irfanullah, Mir; Sharma, Dharmendar Kumar; Chulliyil, Ramya; Layek, Arunasish; De, Suman; Chowdhury, Arindam

    2017-01-01

    Photoluminescence microscopy has been used to interrogate individual nanoaggregates (NAs) of visible light excitable Eu(III)-complex species with 9-hydroxyphenalenone which we found to emit near-white light in methanol. In the solid state however, NAs display diverse emission spectra due to varied sensitization efficiencies, and thereby exhibit a wide range of emission colours. Heterogeneity in sensitization efficiency and asymmetry ratios for Eu-emission is intriguing because all measurable photoluminescence parameters are expected to average out over large number of Eu-complex species which constitute NAs, and suggests the existence of relatively few yet efficient Eu3+ radiative trap centres of varied asymmetry within NAs.

  20. SU-E-J-142: Prompt Gamma Emission Measurements From a Passively Scattered Proton Beam On Targets Containing 16O, 12C and 14N

    Energy Technology Data Exchange (ETDEWEB)

    Jeyasugiththan, J [Department of Physics, University of Cape Town, Cape Town (South Africa); Department of Clinical Oncology, Teaching Hospital, Jeffna (Sri Lanka); Peterson, S [Department of Physics, University of Cape Town, Cape Town (South Africa)

    2015-06-15

    Purpose: To measure the prompt gamma emission from the important elements found in tissue ({sup 16}O,{sup 12}C and {sup 14}N) in a clinical passive-scatter treatment environment. Methods: The targets (composed of water, Perspex, graphite and liquid nitrogen) were irradiated with a 200 MeV passive-scatter proton beam and the discrete prompt gamma energy spectra was detected by a high resolution 2′ × 2′ LaBr. detector. In order to reduce the high level of radiation produced by the beam line elements, the detector was surrounded by 10 cm of lead to attenuate the scattered gamma-rays entering the detector with an extra 5 cm thick layer of lead added along the beam direction. A 10 cm thick collimator with a 5 cm × 10 cm rectangular opening was also used. Results: The prompt gamma peaks at 6.13 MeV and 4.44 MeV were clearly identified as a Result of the inelastic nuclear reaction between the protons and the 16O atoms found in the water target. The 6.13 MeV peak was 5% higher than the peak at 4.44 MeV for the water target. The 4.44 MeV peak was the only identified emission in the prompt gamma energy spectra from the graphite target ({sup 12}C). The expected 2.313 MeV peak form the{sup 14}N (liquid nitrogen target) was identified, but the other expected {sup 14}N peaks could not be resolved. Conclusion: Prompt gamma measurements with a passive-scatter proton beam are possible, but the presence of a high amount of background radiation from the patient final collimator presents a challenge at the treatment isocenter. The prominent prompt gamma peaks at 6.13 MeV and 4.44 MeV were identified from the water, Perspex and graphite targets. The prompt gammas from the liquid nitrogen target were difficult to see, but may not be significant in the in-vivo verification process.

  1. Design of an ultrahigh vacuum transfer mechanism to interconnect an oxide molecular beam epitaxy growth chamber and an x-ray photoemission spectroscopy analysis system.

    Science.gov (United States)

    Rutkowski, M M; McNicholas, K M; Zeng, Zhaoquan; Brillson, L J

    2013-06-01

    We designed a mechanism and the accompanying sample holders to transfer between a VEECO 930 oxide molecular beam epitaxy (MBE) and a PHI Versa Probe X-ray photoemission spectroscopy (XPS) chamber within a multiple station growth, processing, and analysis system through ultrahigh vacuum (UHV). The mechanism consists of four parts: (1) a platen compatible with the MBE growth stage, (2) a platen compatible with the XPS analysis stage, (3) a sample coupon that is transferred between the two platens, and (4) the accompanying UHV transfer line. The mechanism offers a robust design that enables transfer back and forth between the growth chamber and the analysis chamber, and yet is flexible enough to allow transfer between standard sample holders for thin film growth and masked sample holders for making electrical contacts and Schottky junctions, all without breaking vacuum. We used this mechanism to transfer a barium strontium titanate thin film into the XPS analysis chamber and performed XPS measurements before and after exposing the sample to the air. After air exposure, a thin overlayer of carbon was found to form and a significant shift (~1 eV) in the core level binding energies was observed.

  2. Design of an ultrahigh vacuum transfer mechanism to interconnect an oxide molecular beam epitaxy growth chamber and an x-ray photoemission spectroscopy analysis system

    Science.gov (United States)

    Rutkowski, M. M.; McNicholas, K. M.; Zeng, Zhaoquan; Brillson, L. J.

    2013-06-01

    We designed a mechanism and the accompanying sample holders to transfer between a VEECO 930 oxide molecular beam epitaxy (MBE) and a PHI Versa Probe X-ray photoemission spectroscopy (XPS) chamber within a multiple station growth, processing, and analysis system through ultrahigh vacuum (UHV). The mechanism consists of four parts: (1) a platen compatible with the MBE growth stage, (2) a platen compatible with the XPS analysis stage, (3) a sample coupon that is transferred between the two platens, and (4) the accompanying UHV transfer line. The mechanism offers a robust design that enables transfer back and forth between the growth chamber and the analysis chamber, and yet is flexible enough to allow transfer between standard sample holders for thin film growth and masked sample holders for making electrical contacts and Schottky junctions, all without breaking vacuum. We used this mechanism to transfer a barium strontium titanate thin film into the XPS analysis chamber and performed XPS measurements before and after exposing the sample to the air. After air exposure, a thin overlayer of carbon was found to form and a significant shift (˜1 eV) in the core level binding energies was observed.

  3. Design of an ultrahigh vacuum transfer mechanism to interconnect an oxide molecular beam epitaxy growth chamber and an x-ray photoemission spectroscopy analysis system

    Energy Technology Data Exchange (ETDEWEB)

    Rutkowski, M. M.; Zeng Zhaoquan [Department of Physics, Ohio State University, Columbus, Ohio 43210 (United States); McNicholas, K. M. [Department of Electrical and Computer Engineering, Ohio State University, Columbus, Ohio 43210 (United States); Brillson, L. J. [Department of Physics, Ohio State University, Columbus, Ohio 43210 (United States); Department of Electrical and Computer Engineering, Ohio State University, Columbus, Ohio 43210 (United States)

    2013-06-15

    We designed a mechanism and the accompanying sample holders to transfer between a VEECO 930 oxide molecular beam epitaxy (MBE) and a PHI Versa Probe X-ray photoemission spectroscopy (XPS) chamber within a multiple station growth, processing, and analysis system through ultrahigh vacuum (UHV). The mechanism consists of four parts: (1) a platen compatible with the MBE growth stage, (2) a platen compatible with the XPS analysis stage, (3) a sample coupon that is transferred between the two platens, and (4) the accompanying UHV transfer line. The mechanism offers a robust design that enables transfer back and forth between the growth chamber and the analysis chamber, and yet is flexible enough to allow transfer between standard sample holders for thin film growth and masked sample holders for making electrical contacts and Schottky junctions, all without breaking vacuum. We used this mechanism to transfer a barium strontium titanate thin film into the XPS analysis chamber and performed XPS measurements before and after exposing the sample to the air. After air exposure, a thin overlayer of carbon was found to form and a significant shift ({approx}1 eV) in the core level binding energies was observed.

  4. Coupling creep and damage in concrete under high sustained loading: Experimental investigation on bending beams and application of Acoustic Emission technique

    Science.gov (United States)

    Saliba, J.; Loukili, A.; Grondin, F.

    2010-06-01

    effect on concrete, probably because of the consolidation of the hardened cement paste. The influence of creep on fracture energy, fracture toughness, and characteristic length of concrete is also studied. The fracture energy and the characteristic length of concrete increases slightly when creep occurs prior to failure and the size of the fracture process zone increases too. The load-CMOD relationship is linear in the ascending portion and gradually drops off after the peak value in the descending portion. The length of the tail end portion of the softening curve increases with beams subjected to creep. Relatively more ductile fracture behavior was observed with beams subjected to creep. The contribution of non-destructive and instrumental investigation methods is currently exploited to check and measure the evolution of some negative structural phenomena, such as micro-and macro-cracking, finally resulting in a creep-like behaviour. Among these methods, the non-destructive technique based on acoustic Emission proves to be very effective, especially to check and measure micro-cracking that takes place inside a structure under mechanical loading. Thus as a part of the investigation quantitative acoustic emission techniques were applied to investigate microcracking and damage localization in concrete beams. The AE signals were captured with the AE WIN software and further analyzed with Noesis software analysis of acoustic emission data. AE waveforms were generated as elastic waves in concrete due to crack nucleation. And a multichannel data acquisition system was used to record the AE waveforms. During the three point bending tests, quantitative acoustic emission (AE) techniques were used to monitor crack growth and to deduce micro fracture mechanics in concrete beams before and after creep. Several specimens are experimented in order to match each cluster with corresponding damage mechanism of the material under loading. At the same time acoustic emission was used to

  5. Study of gamma-ray emission by proton beam interaction with injected Boron atoms for future medical imaging applications

    Science.gov (United States)

    Petringa, G.; Cirrone, G. A. P.; Caliri, C.; Cuttone, G.; Giuffrida, L.; Larosa, G.; Manna, R.; Manti, L.; Marchese, V.; Marchetta, C.; Margarone, D.; Milluzzo, G.; Picciotto, A.; Romano, F.; Romano, F. P.; Russo, A. D.; Russo, G.; Santonocito, D.; Scuderi, V.

    2017-03-01

    In this work an experimental and theoretical study of gamma-prompt emission has been carried out with the main aim being to understand to what extent this approach can be used during a treatment based on proton-boron fusion therapy. An experimental campaign, carried out with a high purity Germanium detector, has been performed to evaluate the gamma emission from two pure 11B and 10B targets. Furthermore, a set of analytical simulations, using the Talys nuclear reaction code has been performed and the calculated spectra compared with the experimental results. These comparisons allowed us to successfully validate Talys which was then used to estimate the gamma emission when a realistic Boron concentration was considered. Both simulations and experimental results suggest that the gamma emission is low at certain proton energies, thus in order to improve the imaging capabilities, while still maintaining the Boron therapeutic role, we propose the addition of natural Copper bound by a dipyrromethene, BodiPy, to boron atoms. Analytical simulations with Talys suggest that the characteristic spectrum of the copper prompt gamma-rays has several peaks in the energetic regions where the background is negligible.

  6. Measurements of plasma temperature and electron density in laser-induced copper plasma by time-resolved spectroscopy of neutral atom and ion emissions

    Indian Academy of Sciences (India)

    V K Unnikrishnan; Kamlesh Alti; V B Kartha; C Santhosh; G P Gupta; B M Suri

    2010-06-01

    Plasma produced by a 355 nm pulsed Nd:YAG laser with a pulse duration of 6 ns focussed onto a copper solid sample in air at atmospheric pressure is studied spectroscopically. The temperature and electron density characterizing the plasma are measured by time-resolved spectroscopy of neutral atom and ion line emissions in the time window of 300–2000 ns. An echelle spectrograph coupled with a gated intensified charge coupled detector is used to record the plasma emissions. The temperature is obtained using the Boltzmann plot method and the electron density is determined using the Saha– Boltzmann equation method. Both parameters are studied as a function of delay time with respect to the onset of the laser pulse. The results are discussed. The time window where the plasma is optically thin and is also in local thermodynamic equilibrium (LTE), necessary for the laser-induced breakdown spectroscopy (LIBS) analysis of samples, is deduced from the temporal evolution of the intensity ratio of two Cu I lines. It is found to be 700–1000 ns.

  7. GRB hosts through cosmic time - VLT/X-shooter emission-line spectroscopy of 96 GRB-selected galaxies at 0.1 < z < 3.6

    CERN Document Server

    Krühler, T; Fynbo, J P U; Hartoog, O E; Hjorth, J; Jakobsson, P; Perley, D A; Rossi, A; Schady, P; Schulze, S; Tanvir, N R; Vergani, S D; Wiersema, K; Afonso, P M J; Bolmer, J; Cano, Z; Covino, S; D'Elia, V; Postigo, A de Ugarte; Filgas, R; Friis, M; Graham, J F; Greiner, J; Goldoni, P; Gomboc, A; Hammer, F; Japelj, J; Kann, D A; Kaper, L; Klose, S; Levan, A J; Leloudas, G; Milvang-Jensen, B; Guelbenzu, A Nicuesa; Palazzi, E; Pian, E; Piranomonte, S; Sanchez-Ramirez, R; Savaglio, S; Selsing, J; Tagliaferri, G; Vreeswijk, P M; Watson, D J; Xu, D

    2015-01-01

    We present data and initial results from VLT/X-shooter emission-line spectroscopy of 96 GRB-selected galaxies at 0.1spectroscopy available to date. The majority of our GRBs was detected by Swift and 76% are at 0.5emission-line widths (sigma). We find a strong change of the typical physical properties of GRB hosts with redshift. The median SFR, for example, increases from ~0.6 M_sun/yr at z~0.6 up to ~15 M_sun/yr at z~2. A higher ratio of [OIII]/[OII] at higher redshifts leads to an increasing distance of GRB-selected galaxies to the locus of local galaxies in the BPT diagram. Oxygen abundances of the galaxies are distributed between 12+log(O/H)=7.9 and 12+log(O/H)=9.0 with a median of 12+log(O/H)~8.5. The fraction of GRB-selected galaxies with super-solar metallic...

  8. Optical emission spectroscopy study of the expansion dynamics of a laser generated plasma during the deposition of thin films by laser ablation

    Directory of Open Access Journals (Sweden)

    Fazio, Enza

    2007-09-01

    Full Text Available The dynamics of the expanding plasma produced by excimer laser ablation of different materials such as silicon, silicon carbide, graphite and tin powder were studied by means of time integrated, spatially resolved emission spectroscopy and fast photography imaging of the expanding plasma. Experiments were performed both in vacuum and in different pure background atmosphere (i.e. oxygen or nitrogen and, finally, in gaseous mixtures (i.e. in O2/Ar and N2/Ar mixtures. These investigations were performed to gather information on the nature of the chemical species present in the plasma and on the occurrence of chemical reactions during the interaction between the plasma and the background gas. Then, we tried to correlate the plasma expansion dynamics to the structural and physical properties of the deposited materials. Experimental results clearly indicate that there is a strong correlation between the plasma expansion dynamics and the structural properties of the deposited thin films. In this respect, the investigations performed by means of fast photography and of optical emission spectroscopy revealed themselves as powerful tools for an efficient control of the deposition process itself.

  9. Monte Carlo simulation of photon emission below a few hundred kiloelectronvolts for beam monitoring in carbon ion therapy

    Science.gov (United States)

    Yamaguchi, Mitsutaka; Nagao, Yuto; Satoh, Takahiro; Sugai, Hiroyuki; Sakai, Makoto; Arakawa, Kazuo; Kawachi, Naoki

    2017-01-01

    The purpose of this study is to determine whether the main component of the low-energy (63-68 keV) particles emitted perpendicularly to the 12C beam from the 12C-irradiated region in a water phantom is secondary electron bremsstrahlung (SEB). Monte Carlo simulations of a 12C-beam (290 MeV/u) irradiated on a water phantom were performed. A detector was placed beside the water phantom with a lead collimator between the phantom and the detector. To move the Bragg-peak position, a binary filter was placed in an upper stream of the phantom. The energy distributions of the particles incident on the detector and those deposited in the detector were analyzed. The simulation was also performed with suppressed delta-ray and/or bremsstrahlung generation to identify the SEB components. It was found that the particles incident on the detector were predominantly photons and neutrons. The yields of the photons and energy deposition decreased with the suppression of SEB generation. It is concluded that one of the predominant components of the yields in the regions shallower than the Bragg-peak position is due to SEB generation, and these components become significantly smaller in regions deeper than the Bragg-peak position.

  10. Time-resolved measurement of atomic emission enhancement by fs-ns dual-pulsed laser-induced breakdown spectroscopy

    Institute of Scientific and Technical Information of China (English)

    Yan Li-Xin; Zhang Yong-Sheng; Zheng Guo-Xin; Liu Jing-Ru; Cheng Jian-Ping; Lü Min

    2006-01-01

    Time-resolved measurement of atomic emission enhancement is performed by using a 500-fs KrF laser pulse incident upon a high density supersonic O2 gas jet, synchronized with an orthogonal ns frequency-doubled Nd:YAG laser pulse. The ultra-short pulse serves as an igniter of the gas jet, and the subsequent ns-laser pulse significantly enhances the atomic emission. Analysis shows that the contributions to the enhancement effect are made mainly by the bremsstrahlung radiation and cascade ionization.

  11. Potential radionuclide emissions from stacks on the Hanford site, Part 2: Dose assessment methodology using portable low-resolution gamma spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Barnett, J.M. [Westinghouse Hanford Company, Richland, WA (United States)

    1995-02-01

    In September 1992, the Westinghouse Hanford Company began developing an in situ measurement method to assess gamma radiation emanating from high-efficiency particulate air filters using portable low-resolution gamma spectroscopy. The purpose of the new method was to assess radioactive exhaust stack air emissions from empirical data rather than from theoretical models and to determine the potential unabated dose to an offsite theoretical maximally exposed individual. In accordance with Title 40, Code of Federal Regulations, Part 61, Subpart H, {open_quotes}National Emission Standards for Hazardous Air Pollutants{close_quotes}, stacks that have the potential to emit {ge} 1 {mu}Sv y{sup {minus}1} (0.1 mrem y{sup {minus}1}) to the maximally exposed individual are considered {open_quotes}major{close_quotes} and must meet the continuous monitoring requirements. After the method was tested and verified, the U.S. Environmental Protection Agency, Region 10, approved its use in June 1993. Of the 125 stacks operated by the Westinghouse Hanford Company, 22 were targeted for evaluation by this method, and 15 were assessed. (The method could not be applied at seven stacks because of excessive background radiation or because no gamma emitting particles appear in the emission stream.) The most significant result from this study was the redesignation of the T Plant main stack. The stack was assessed as being {open_quotes}minor{close_quotes}, and it now only requires periodic confirmatory measurements and meets federally imposed sampling requirements.

  12. 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.

  13. Exploration of CdTe quantum dots as mesoscale pressure sensors via time-resolved shock-compression photoluminescent emission spectroscopy

    Science.gov (United States)

    Kang, Zhitao; Banishev, Alexandr A.; Lee, Gyuhyon; Scripka, David A.; Breidenich, Jennifer; Xiao, Pan; Christensen, James; Zhou, Min; Summers, Christopher J.; Dlott, Dana D.; Thadhani, Naresh N.

    2016-07-01

    The nanometer size of CdTe quantum dots (QDs) and their unique optical properties, including size-tunable narrow photoluminescent emission, broad absorption, fast photoluminescence decay, and negligible light scattering, are ideal features for spectrally tagging the shock response of localized regions in highly heterogeneous materials such as particulate media. In this work, the time-resolved laser-excited photoluminescence response of QDs to shock-compression was investigated to explore their utilization as mesoscale sensors for pressure measurements and in situ diagnostics during shock loading experiments. Laser-driven shock-compression experiments with steady-state shock pressures ranging from 2.0 to 13 GPa were performed on nanocomposite films of CdTe QDs dispersed in a soft polyvinyl alcohol polymer matrix and in a hard inorganic sodium silicate glass matrix. Time-resolved photoluminescent emission spectroscopy was used to correlate photoluminescence changes with the history of shock pressure and the dynamics of the matrix material surrounding the QDs. The results revealed pressure-induced blueshifts in emitted wavelength, decreases in photoluminescent emission intensity, reductions in peak width, and matrix-dependent response times. Data obtained for these QD response characteristics serve as indicators for their use as possible time-resolved diagnostics of the dynamic shock-compression response of matrix materials in which such QDs are embedded as in situ sensors.

  14. Interactions of protons with furan molecules studied by collision-induced emission spectroscopy at the incident energy range of 50-1000 eV

    Science.gov (United States)

    Wasowicz, Tomasz J.; Pranszke, Boguslaw

    2016-08-01

    Investigations of the ion-molecule reactions provide insight into many fields ranging from the stellar wind interaction with interstellar media, up to medicine and industrial applications. Besides the applications, the understanding of these processes is itself a problem of fundamental importance. Thus, interactions of protons with the gas-phase furan molecules have been investigated for the first time in the energy range of 50-1000 eV exploiting collision-induced emission spectroscopy. Recorded spectra reveal emission of the atomic H β to H θ lines of the hydrogen Balmer series and the molecular bands of vibrationally and rotationally excited diatomic CH fragments created in the A2 Δ and B2Σ- electronic states. The measurements of the emission yields of the excited fragments by recording their intensities at different projectile energies have been performed. The highest yields have been observed for production of hydrogen atoms which intensities rapidly decreased with increasing principal quantum number n . From the H ( n = 4-7) intensity ratios depopulation factors of hydrogen excited states have been determined at each impact energy and possible collisional mechanisms leading to enhanced production of the hydrogen atoms have been suggested. We compare and discuss our results with improved data set of proton collisions with tetrahydrofuran (THF) molecules, the hydrogenated derivatives of furan.

  15. Photolysis of n-butyl nitrite and isoamyl nitrite at 355 nm: A time-resolved Fourier transform infrared emission spectroscopy and ab initio study

    CERN Document Server

    Ji, Min; Zhang, Qun; Chen, Yang

    2009-01-01

    We report on the photodissociation dynamics study of n-butyl nitrite (n-C_4H_9ONO) and isoamyl nitrite ((CH_3)_2C_3H_5ONO) by means of time-resolved Fourier transform infrared (TR-FTIR) emission spectroscopy. The obtained TR-FTIR emission spectra of the nascent NO fragments produced in the 355-nm laser photolysis of the two alkyl nitrite species showed an almost identical rotational temperature and vibrational distributions of NO. In addition, a close resemblance between the two species was also found in the measured temporal profiles of the IR emission of NO and the recorded UV absorption spectra. The experimental results are consistent with our ab initio calculations using the time-dependent density functional theory at the B3LYP/6-311G(d,p) level, which indicate that the substitution of one of the two {gamma}-H atoms in n-C_4H_9ONO with a methyl group to form (CH_3)_2C_3H_5ONO has only a minor effect on the photodissociation dynamics of the two molecules.

  16. Selective area growth of In(Ga)N/GaN nanocolumns by molecular beam epitaxy on GaN-buffered Si(111): from ultraviolet to infrared emission.

    Science.gov (United States)

    Albert, S; Bengoechea-Encabo, A; Sánchez-García, M A; Kong, X; Trampert, A; Calleja, E

    2013-05-03

    Selective area growth of In(Ga)N/GaN nanocolumns was performed on GaN-buffered Si(111) substrates by plasma-assisted molecular beam epitaxy. Undoped and Si-doped GaN buffer layers were first grown on Si(111) substrates, showing photoluminescence excitonic emission without traces of other low energy contributions, in particular, the yellow band. The GaN buffer surface roughness (between 10 and 14 nm, the rms value in a 10 × 10 μm(2) area) was low enough to allow the fabrication of a thin (7 nm thick) well defined Ti nanohole mask, for the selective area growth. Ordered In(Ga)N/GaN nanocolumns emitting from the ultraviolet (3.2 eV) to the infrared (0.78 eV) were obtained. The morphology and the emission efficiency of the In(Ga)N/GaN nanocolumns emitting at a given wavelength could be substantially improved by tuning the In/Ga and total III/N ratios. An estimated internal quantum efficiency of 36% was derived from photoluminescence data for green emitting nanocolumns.

  17. Selective area growth of In(Ga)N/GaN nanocolumns by molecular beam epitaxy on GaN-buffered Si(111): from ultraviolet to infrared emission

    Science.gov (United States)

    Albert, S.; Bengoechea-Encabo, A.; Sánchez-García, M. A.; Kong, X.; Trampert, A.; Calleja, E.

    2013-05-01

    Selective area growth of In(Ga)N/GaN nanocolumns was performed on GaN-buffered Si(111) substrates by plasma-assisted molecular beam epitaxy. Undoped and Si-doped GaN buffer layers were first grown on Si(111) substrates, showing photoluminescence excitonic emission without traces of other low energy contributions, in particular, the yellow band. The GaN buffer surface roughness (between 10 and 14 nm, the rms value in a 10 × 10 μm2 area) was low enough to allow the fabrication of a thin (7 nm thick) well defined Ti nanohole mask, for the selective area growth. Ordered In(Ga)N/GaN nanocolumns emitting from the ultraviolet (3.2 eV) to the infrared (0.78 eV) were obtained. The morphology and the emission efficiency of the In(Ga)N/GaN nanocolumns emitting at a given wavelength could be substantially improved by tuning the In/Ga and total III/N ratios. An estimated internal quantum efficiency of 36% was derived from photoluminescence data for green emitting nanocolumns.

  18. Prediction of methane emission from lactating dairy cows using milk fatty acids and mid-infrared spectroscopy

    NARCIS (Netherlands)

    Derksen-van Gastelen, Sanne; Dijkstra, Jan

    2016-01-01

    Enteric methane (CH4) production is among the main targets of greenhouse gas mitigation practices for the dairy industry. A simple, robust and inexpensive measurement technique applicable on a large scale to estimate CH4 emission from dairy cattle would therefore be valuable

  19. Near-Infrared Spectroscopy of Faint Discrete X-ray Point Sources Constituting the Galactic Ridge X-ray Emission

    CERN Document Server

    Morihana, Kumiko; Dubath, Pierre; Yoshida, Tessei; Suzuki, Kensuke; Ebisawa, Ken

    2016-01-01

    The Galactic Ridge X-ray Emission (GRXE) is apparently extended X-ray emission along the Galactic Plane. The X-ray spectrum is characterized by hard continuum with a strong Fe K emission feature in the 6-7 keV band. A substantial fraction (~80%) of the GRXE in the Fe band was resolved into point sources by deep Chandra imaging observations, thus GRXE is mostly composed of dim Galactic X-ray point sources at least in this energy band. To investigate the populations of these dim X-ray point sources, we carried out Near-Infrared (NIR) follow-up spectroscopic observations in two deep Chandra fields located in the Galactic plane at (l,b)=(0.1{\\arcdeg}, -1.4{\\arcdeg}) and (28.5{\\arcdeg}, 0.0{\\arcdeg}) using NTT/SofI and Subaru/MOIRCS. We obtained well-exposed NIR spectra from 65 objects and found that there are three main classes of Galactic sources based on the X-ray color and NIR spectral features: those having (A) hard X-ray spectra and NIR emission features such as HI(Br{\\gamma}), HeI, and HeII (2 objects), (B)...

  20. Room temperature Ultraviolet B emission from InAlGaN films synthesized by plasma-assisted molecular beam epitaxy

    Energy Technology Data Exchange (ETDEWEB)

    Kong, W., E-mail: wei.kong@duke.edu; Jiao, W. Y.; Kim, T. H.; Brown, A. S. [Department of Electrical and Computer Engineering, Duke University, Durham, North Carolina 27708 (United States); Roberts, A. T. [Charles Bowden Laboratory, Army Aviation and Missile RD& E Center, Redstone Arsenal, Alabama 35898 (United States); Fournelle, J. [Department of Geoscience, University of Wisconsin, Madison, Wisconsin 53706 (United States); Losurdo, M. [CNR-NANOTEC, Istituto di Nanotecnologia, via Orabona, 4-70126 Bari (Italy); Everitt, H. O. [Charles Bowden Laboratory, Army Aviation and Missile RD& E Center, Redstone Arsenal, Alabama 35898 (United States); Department of Physics, Duke University, Durham, North Carolina 27708 (United States)

    2015-09-28

    Thin films of the wide bandgap quaternary semiconductor In{sub x}Al{sub y}Ga{sub (1−x−y)}N with low In (x = 0.01–0.05) and high Al composition (y = 0.40–0.49) were synthesized on GaN templates by plasma-assisted molecular beam epitaxy. High-resolution X-ray diffraction was used to correlate the strain accommodation of the films to composition. Room temperature ultraviolet B (280 nm–320 nm) photoluminescence intensity increased with increasing In composition, while the Stokes shift remained relatively constant. The data suggest a competition between radiative and non-radiative recombination occurs for carriers, respectively, localized at centers produced by In incorporation and at dislocations produced by strain relaxation.

  1. Advanced techniques for actinide spectroscopy (ATAS 2012). Abstract book

    Energy Technology Data Exchange (ETDEWEB)

    Foerstendorf, Harald; Mueller, Katharina; Steudtner, Robin (eds.)

    2012-07-01

    The abstract book of the International workshop on advanced techniques for actinide spectroscopy (ATAS 2012) include contributions concerning the following issues: environmental applications, NMR spectroscopy, vibrational spectroscopy, X-ray spectroscopy and theory, technical application: separation processes, emission spectroscopy.

  2. Observation of Atomic Emission Enhancement by fs-ns Dual-Pulse Laser-Induced Breakdown Spectroscopy

    Institute of Scientific and Technical Information of China (English)

    YAN Li-Xin; ZHANG Yong-Sheng; ZHANG Li-Rong; LIU Jing-Ru; CHENG Jian-Ping; L(U) Min

    2006-01-01

    An experiment of a 500-fs KrF laser pulse incident upon a high density supersonic O2 gas jet synchronously with an ns frequency-doubled Nd:YAG laser pulse is performed in orthogonal configuration.Significant atomic emission enhancement of over forty-fold is observed with an optical multi-channel analyser.The enhancement effect is probably attributed to the different ionization mechanisms between fs and ns laser pulses.

  3. Electron density in amplitude modulated microwave atmospheric plasma jet as determined from microwave interferometry and emission spectroscopy

    Science.gov (United States)

    Faltýnek, J.; Hnilica, J.; Kudrle, V.

    2017-01-01

    Time resolved electron density in an atmospheric pressure amplitude modulated microwave plasma jet is determined using the microwave interferometry method, refined by numerical modelling of the propagation of non-planar electromagnetic waves in the vicinity of a small diameter, dense collisional plasma filament. The results are compared to those from the Stark broadening of the {{\\text{H}}β} emission line. Both techniques show, both qualitatively and quantitatively, a similar temporal evolution of electron density during one modulation period.

  4. Excited State Chemistry in the Free Stream of the NASA IHF Arc Jet Facility Observed by Emission Spectroscopy

    Science.gov (United States)

    Winter, Michael W.; Prabhu, Dinesh K.

    2011-01-01

    Spectroscopic measurements of non-equilibrium emission were made in the free stream of the 60 megawatts Interaction Heating Facility at NASA Ames Research Center. In the visible near infrared wavelength region, the most prominent emission was from molecular N2, and in the ultra violet region, the spectra were dominated by emission from molecular NO. The only atomic lines observed were those of copper (an erosion product of the electrodes). The bands of the 1st Positive system of N2 (if B is true then A is true) differed significantly from spectra computed spectra assuming only thermal excitation, suggesting overpopulation of the high vibrational states of the B state of N2. Populations of these high vibrational levels (peaking at v (sub upper) equals 13) of the N2 B state were determined by scaling simulated spectra; calculations were performed for each upper vibrational state separately. The experimental-theoretical procedure was repeated for several radial positions away from the nozzle axis to obtain spatial distributions of the upper state populations; rotational symmetry of the flow was assumed in simulations. The overpopulation of the high vibrational levels has been interpreted as the effect of inverse pre-dissociation of neutral atoms in the N2 A state, which populates the N2 B state through a level crossing process at v (sub upper) is greater than 10.

  5. Influence of COsub>2sub> pressure on the emission spectra and plasma parameters in underwater laser-induced breakdown spectroscopy.

    Science.gov (United States)

    Goueguel, Christian L; McIntyre, Dustin L; Jain, Jinesh C

    2016-12-01

    Optical emission spectroscopic studies have been carried out to investigate the pressure effect of COsub>2sub> on laser-produced underwater plasma. The plasma was generated by focusing 1064 nm, 6 ns pulses from a Nd:YAG laser in a COsub>2sub>-bearing solution. The temporal evolution of the continuum emission, Sr and Ba lines, and plasma electron density and temperature was characterized under COsub>2sub> pressure ranging from 10 to 300 bars. The electron density measurements were made using the Stark broadening of the 455.40 nm Ba II line, while the temperature measurements have been performed by the Saha-Boltzmann method using the Sr I-II lines at 460.73 and 407.77 nm, respectively. It was found that COsub>2sub> pressure has little effect on the emission line intensity and signal-to-background ratio. The electron density and the temperature are found to be independent of the COsub>2sub> pressure at early times. When time becomes longer, the electron density exhibits an appreciable rise as the COsub>2sub> pressure increases, while the temperature is found to be unchanged.

  6. Energy-dispersive x-ray fluorescence spectroscopy and inductively coupled plasma emission spectrometry evaluated for multielement analysis in complex biological matrices.

    Science.gov (United States)

    Irons, R D; Schenk, E A; Giauque, R D

    1976-12-01

    Energy-dispersive x-ray spectroscopy and inductively coupled plasma emission spectrometry were evaluated as methods for routine multielement analysis of biological material. Standard samples included Standard Reference Materials (National Bureau of Standards), compounded mixtures, and supplements that provided a wide range of elemental concentrations for analysis. Elements included in this study were Zn, Pb, Ni, Mn, Fe, Mg, Cu, Ca, As, Se, Br, Rb, and Sr. Standards were analyzed as unknowns by participating laboratories. The two methods were evaluated for sensitivity, precision, and accuracy, and the results compared to those obtained for atomic absorption spectrometric analysis of identical standard unknowns. Both methods compared favorably and both were determined to be highly reliable for such an application. Advantages and disadvantages of each method are compared and discussed.

  7. Delocalization and occupancy effects of 5f orbitals in plutonium intermetallics using L3-edge resonant X-ray emission spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Booth, C. H.; Medling, S. A.; Jiang, Yu; Bauer, E. D.; Tobash, P. H.; Mitchell, J. N.; Veirs, D. K.; Wall, M. A.; Allen, P. G.; Kas, J. J.; Sokaras, D.; Nordlund, D.; Weng, T. -C.

    2014-06-24

    Although actinide (An) L3 -edge X-ray absorption near-edge structure (XANES) spectroscopy has been very effective in determining An oxidation states in insulating, ionically bonded materials, such as in certain coordination compounds and mineral systems, the technique fails in systems featuring more delocalized 5f orbitals, especially in metals. Recently, actinide L3-edge resonant X-ray emission spec- troscopy (RXES) has been shown to be an effective alternative. This technique is further demonstrated here using a parameterized partial unoccupied density of states method to quantify both occupancy and delocalization of the 5f orbital in ?-Pu, ?-Pu, PuCoGa5 , PuCoIn5 , and PuSb2. These new results, supported by FEFF calculations, highlight the effects of strong correlations on RXES spectra and the technique?s ability to differentiate between f-orbital occupation and delocalization.

  8. Electron correlation energy of La sub x Sr sub 1 sub - sub x TiO sub 3 by high-resolution soft-X-ray emission spectroscopy

    CERN Document Server

    Higuchi, T; Tsukamoto, T; Harada, Y; Taguchi, Y; Tokura, Y; Shin, S

    2003-01-01

    The electronic structure of La sub x Sr sub 1 sub - sub x TiO sub 3 (x<=0.10) has been investigated by high-resolution soft-X-ray emission spectroscopy (SXES) spectra in the Ti 2p energy region. At the t sub 2 sub g -resonance SXES spectra, the d-d transition whose Raman shift is about 2.2 eV corresponds to the magnitude of the half intra-atomic Coulomb energy (U sub d sub d /2). The magnitude does not change in x<=0.10. This fact is consistent with the results obtained from the effective mass and the electronic specific heat.

  9. Application of inductively coupled plasma atomic emission spectroscopy analysis with a polychromator/monochromator combination the byproducts of coal-fired power stations

    Science.gov (United States)

    Weers, C. A.

    The by-products of coal-fired power plants may be hazardous for the environment. Good analysis methods are therefore required in order to establish either a possible usage of the by-products or their possible storage. Preliminary experiments performed with inductively coupled plasma atomic emission spectroscopy have proven very successful. Moreover, the method is cost-effective. A short description is given of the optimized system for routine analysis. The system consists of a 2- and a 15-channel polychromator in combination with a monochromator. The opportunities is provides are also described. Use of the monochromator to analyze coal and run-off water from the flue-gases desulphurization, and of the polychromators to analyze coal fly-ash is described separately.

  10. Study of effect of H2 addition on the production of fluorocarbon radicals in H2/C4F8 inductively coupled plasma via optical emission spectroscopy actinometry

    Institute of Scientific and Technical Information of China (English)

    Huang Song; Xin Yu; Ning Zhao-Yuan

    2005-01-01

    C4F8 plasma with the addition of H2 is generated by the inductively coupled plasma (ICP) method. The relative densities of CF, CF2, H and F radicals are determined by actinometric optical emission spectroscopy (AOES) as a function of the gas flow rate ratio R=H2/(H2+C4F8) at a pressure of 0.8 Pa and an input r.f. power of 400W, while that of HF is measured by quadrupole mass spectrometry (QMS). The results show that plasma activity increases firstly and then decreases with increasing R. As the gas flow rate ratio R changes from 0 to 0.625, relative densities of both CF and CF2 decrease, and the relative [CF] has a similar tendency as the calculated [CF], indicating that CF radicals are generated mainly by the electron impact dissociation of CF2 radicals. Production of HF is also discussed.

  11. Pattern recognition of Inductively Coupled Plasma Atomic Emission Spectroscopy of human scalp hair for discriminating between healthy and Hepatitis C patients

    Energy Technology Data Exchange (ETDEWEB)

    Lloyd, Gavin R. [Centre for Chemometrics, School of Chemistry, University of Bristol, Cantocks Close, Bristol BS2 8DF (United Kingdom); Ahmad, Sajjad [Department of Chemistry, Quaid-i-Azam University, Islamabad 45320 (Pakistan); Wasim, Mohammad [Chemistry Division, Pakistan Institute of Nuclear Science and Technology, P.O. Nilore, Islamabad (Pakistan); Brereton, Richard G., E-mail: r.g.brereton@bris.ac.uk [Centre for Chemometrics, School of Chemistry, University of Bristol, Cantocks Close, Bristol BS2 8DF (United Kingdom)

    2009-09-01

    Inductively Coupled Plasma Atomic Emission Spectroscopy measurements of six trace elements were performed on the scalp hair of 155 donors, 73 of which have been diagnosed with Hepatitis C and 82 Controls. Principal Components Analysis (PCA) was employed to visualise the separation between groups and show the relationship between the elements and the diseased state. Pattern recognition methods for classification involving Quadratic Discriminant Analysis and Partial Least Squares Discriminant Analysis (PLS-DA) were applied to the data. The number of significant components for both PCA and PLS were determined using the bootstrap. The stability of training set models were determined by repeatedly splitting the data into training and test sets and employing visualisation for two components models: the percent classification ability (CC), predictive ability (PA) and model stability (MS) were computed for test and training sets.

  12. Analysis of the absorption spectra of gas emission of patients with lung cancer and chronic obstructive pulmonary disease by laser optoacoustic spectroscopy

    Science.gov (United States)

    Bukreeva, Ekaterina B.; Bulanova, Anna A.; Kistenev, Yurii V.; Kuzmin, Dmitry A.; Tuzikov, Sergei A.; Yumov, Evgenii L.

    2013-02-01

    It is important to identify patients with chronic obstructive pulmonary disease (COPD) and lung cancer in the early stages of the disease. The method of laser opto-acoustic gas analysis, in this case, can act as a promising tool for diagnostics. The material for this study were the gas emission samples collected from patients and healthy volunteers - samples of exhaled air, swabs from teeth and cheeks. A set of material was formed three groups: healthy volunteers, patients with COPD, lung cancer patients. The resulting samples were analyzed by means of laser opto-acoustic gas analyzers: with intracavity location detector (ILPA-1), with extracavity location detector (LGA-2). Presentation of the results in an easy to visual form was performed using the method of elastic maps, based on the principal component analysis. The results of analysis show potentialities of usage of laser optoacoustic spectroscopy application to assess the status of patients with chronic obstructive pulmonary disease and lung cancer.

  13. Current opportunities and challenges of magnetic resonance spectroscopy, positron emission tomography, and mass spectrometry imaging for mapping cancer metabolism in vivo.

    Science.gov (United States)

    Lin, Gigin; Chung, Yuen-Li

    2014-01-01

    Cancer is known to have unique metabolic features such as Warburg effect. Current cancer therapy has moved forward from cytotoxic treatment to personalized, targeted therapies, with some that could lead to specific metabolic changes, potentially monitored by imaging methods. In this paper we addressed the important aspects to study cancer metabolism by using image techniques, focusing on opportunities and challenges of magnetic resonance spectroscopy (MRS), dynamic nuclear polarization (DNP)-MRS, positron emission tomography (PET), and mass spectrometry imaging (MSI) for mapping cancer metabolism. Finally, we highlighted the future possibilities of an integrated in vivo PET/MR imaging systems, together with an in situ MSI tissue analytical platform, may become the ultimate technologies for unraveling and understanding the molecular complexities in some aspects of cancer metabolism. Such comprehensive imaging investigations might provide information on pharmacometabolomics, biomarker discovery, and disease diagnosis, prognosis, and treatment response monitoring for clinical medicine.

  14. Observation of Coriolis Coupling between nu(2) + 4nu(4) and 7nu(4) in Acetylene &Xtilde;(1)Sigma(+)(g) by Stimulated Emission Pumping Spectroscopy.

    Science.gov (United States)

    Moss; Duan; Jacobson; O'Brien; Field

    2000-02-01

    Stimulated emission pumping (SEP) spectroscopy has been used to examine a low energy region (E(vib) approximately 4400 cm(-1)) of &Xtilde;(1)Sigma(+)(g) acetylene at higher resolution than was possible in previous dispersed fluorescence studies. The expected bright state, nu(2) + 4nu(4), is observed to be coupled to the nearly degenerate 7nu(4) state by a Coriolis mechanism. A least-squares analysis yields values for zero-order vibrational energies, rotational constants, and a Coriolis-coupling coefficient that are all consistent with expectations. Calculated relative intensities of SEP transitions, accounting for interference due to axis-switching effects, are also consistent with observations. Implications of the observed Coriolis resonance with regard to global acetylene vibrational dynamics are also discussed. Copyright 2000 Academic Press.

  15. Highly polarized emission in spin resolved photoelectron spectroscopy of alpha-Fe(001)/GaAs(001)

    Energy Technology Data Exchange (ETDEWEB)

    Tobin, James; Yu, Sung Woo; Morton, Simon; Waddill, George; Thompson, Jamie; Neal, James; Spangenberg, Matthais; Shen, T.H.

    2009-05-19

    Highly spin-polarized sources of electrons, Integrated into device design, remain of great interest to the spintronic and magneto-electronic device community Here, the growth of Fe upon GaAs(001) has been studied with photoelectron spectroscopy (PES), including Spin Resolved PES. Despite evidence of atomic level disorder such as intermixing, an over-layer with the spectroscopic signature of alpha-Fe(001), with a bcc real space ordering, Is obtained The results will be discussed in light of the possibility of using such films as a spin-polarized source in device applications.

  16. Spectral and spatial resolution of the 12.8 micron Ne 2 emission from the galactic center. [astronomical spectroscopy/emission spectra, radio sources (astronomy)

    Science.gov (United States)

    Wollman, E. R.; Geballe, T. R.; Lacy, J. H.; Townes, C. H.; Rank, D. M.

    1975-01-01

    High-resolution spectra of the Ne II 12.8 micron fine-structure line in emission from the galactic center cloud Sgr A West show a line-center LSR radial velocity of + 75 + or - 20 km/sec. and a velocity dispersion of about 200 km/sec. The line has been observed with spectral resolution as high as 0.10/cm and spatial resolution as high as 8 sec. This appears to provide a direct measurement of conditions in the 45 sec. ionized region at the galactic center. The radial velocity and dispersion are more-or-less independent of position and indicate that events as recent as the last 4 million years have given the ionized gas a systematic motion with respect to the massive stellar component of material at the galactic center. An upper limit for the mass approximately equal to four million times the solar mass was obtained from the velocity distribution, with the mass located within 0.8 parsecs of the galactic center.

  17. Quantifying aflatoxins in peanuts using fluorescence spectroscopy coupled with multi-way methods: Resurrecting second-order advantage in excitation-emission matrices with rank overlap problem

    Science.gov (United States)

    Sajjadi, S. Maryam; Abdollahi, Hamid; Rahmanian, Reza; Bagheri, Leila

    2016-03-01

    A rapid, simple and inexpensive method using fluorescence spectroscopy coupled with multi-way methods for the determination of aflatoxins B1 and B2 in peanuts has been developed. In this method, aflatoxins are extracted with a mixture of water and methanol (90:10), and then monitored by fluorescence spectroscopy producing EEMs. Although the combination of EEMs and multi-way methods is commonly used to determine analytes in complex chemical systems with unknown interference(s), rank overlap problem in excitation and emission profiles may restrain the application of this strategy. If there is rank overlap in one mode, there are several three-way algorithms such as PARAFAC under some constraints that can resolve this kind of data successfully. However, the analysis of EEM data is impossible when some species have rank overlap in both modes because the information of the data matrix is equivalent to a zero-order data for that species, which is the case in our study. Aflatoxins B1 and B2 have the same shape of spectral profiles in both excitation and emission modes and we propose creating a third order data for each sample using solvent as a new additional selectivity mode. This third order data, in turn, converted to the second order data by augmentation, a fact which resurrects the second order advantage in original EEMs. The three-way data is constructed by stacking augmented data in the third way, and then analyzed by two powerful second order calibration methods (BLLS-RBL and PARAFAC) to quantify the analytes in four kinds of peanut samples. The results of both methods are in good agreement and reasonable recoveries are obtained.

  18. Quantifying aflatoxins in peanuts using fluorescence spectroscopy coupled with multi-way methods: Resurrecting second-order advantage in excitation-emission matrices with rank overlap problem.

    Science.gov (United States)

    Sajjadi, S Maryam; Abdollahi, Hamid; Rahmanian, Reza; Bagheri, Leila

    2016-03-05

    A rapid, simple and inexpensive method using fluorescence spectroscopy coupled with multi-way methods for the determination of aflatoxins B1 and B2 in peanuts has been developed. In this method, aflatoxins are extracted with a mixture of water and methanol (90:10), and then monitored by fluorescence spectroscopy producing EEMs. Although the combination of EEMs and multi-way methods is commonly used to determine analytes in complex chemical systems with unknown interference(s), rank overlap problem in excitation and emission profiles may restrain the application of this strategy. If there is rank overlap in one mode, there are several three-way algorithms such as PARAFAC under some constraints that can resolve this kind of data successfully. However, the analysis of EEM data is impossible when some species have rank overlap in both modes because the information of the data matrix is equivalent to a zero-order data for that species, which is the case in our study. Aflatoxins B1 and B2 have the same shape of spectral profiles in both excitation and emission modes and we propose creating a third order data for each sample using solvent as a new additional selectivity mode. This third order data, in turn, converted to the second order data by augmentation, a fact which resurrects the second order advantage in original EEMs. The three-way data is constructed by stacking augmented data in the third way, and then analyzed by two powerful second order calibration methods (BLLS-RBL and PARAFAC) to quantify the analytes in four kinds of peanut samples. The results of both methods are in good agreement and reasonable recoveries are obtained.

  19. Measurement of the hot spot electron temperature in NIF ICF implosions using Krypton x-ray emission spectroscopy

    Science.gov (United States)

    Ma, T.; Chen, H.; Patel, P. K.; Schneider, M.; Barrios, M.; Berzak Hopkins, L.; Casey, D.; Chung, H.-K.; Hammel, B.; Jarrott, C.; Nora, R.; Pak, A.; Scott, H.; Spears, B.; Weber, C.

    2015-11-01

    The inference of ion temperature from neutron spectral measurements in indirect-drive ICF implosions is known to be sensitive to non-thermal velocity distributions in the fuel. The electron temperature (Te) inferred from dopant line ratios should not be sensitive to these bulk motions and hence may be a better measure of the thermal temperature of the hot spot. Here we describe a series of experiments to be conducted on the NIF where a small